cathode ray experiment was done by

• Structure of Atom

Cathode Ray Experiment

What is cathode ray tube.

A cathode-ray tube (CRT) is a vacuum tube in which an electron beam, deflected by applied electric or magnetic fields, produces a trace on a fluorescent screen.

The function of the cathode ray tube is to convert an electrical signal into a visual display. Cathode rays or streams of electron particles are quite easy to produce, electrons orbit every atom and move from atom to atom as an electric current.

Table of Contents

Cathode ray tube, recommended videos.

• J.J.Thomson Experiment

Apparatus Setup

Procedure of the experiment.

• Frequently Asked Questions – FAQs

In a cathode ray tube, electrons are accelerated from one end of the tube to the other using an electric field. When the electrons hit the far end of the tube they give up all the energy they carry due to their speed and this is changed to other forms such as heat. A small amount of energy is transformed into X-rays.

The cathode ray tube (CRT), invented in 1897 by the German physicist Karl Ferdinand Braun, is an evacuated glass envelope containing an electron gun a source of electrons and a fluorescent light, usually with internal or external means to accelerate and redirect the electrons. Light is produced when electrons hit a fluorescent tube.

The electron beam is deflected and modulated in a manner that allows an image to appear on the projector. The picture may reflect electrical wave forms (oscilloscope), photographs (television, computer monitor), echoes of radar-detected aircraft, and so on. The single electron beam can be processed to show movable images in natural colours.

J. J. Thomson Experiment – The Discovery of Electron

The Cathode ray experiment was a result of English physicists named J. J. Thomson experimenting with cathode ray tubes. During his experiment he discovered electrons and it is one of the most important discoveries in the history of physics. He was even awarded a Nobel Prize in physics for this discovery and his work on the conduction of electricity in gases.

However, talking about the experiment, J. J. Thomson took a tube made of glass containing two pieces of metal as an electrode. The air inside the chamber was subjected to high voltage and electricity flowing through the air from the negative electrode to the positive electrode.

J. J. Thomson designed a glass tube that was partly evacuated, i.e. all the air had been drained out of the building. He then applied a high electric voltage at either end of the tube between two electrodes. He observed a particle stream (ray) coming out of the negatively charged electrode (cathode) to the positively charged electrode (anode). This ray is called a cathode ray and is called a cathode ray tube for the entire construction.

The experiment Cathode Ray Tube (CRT) conducted by J. J. Thomson, is one of the most well-known physical experiments that led to electron discovery . In addition, the experiment could describe characteristic properties, in essence, its affinity to positive charge, and its charge to mass ratio. This paper describes how J is simulated. J. Thomson experimented with Cathode Ray Tube.

The major contribution of this work is the new approach to modelling this experiment, using the equations of physical laws to describe the electrons’ motion with a great deal of accuracy and precision. The user can manipulate and record the movement of the electrons by assigning various values to the experimental parameters.

A Diagram of JJ.Thomson Cathode Ray Tube Experiment showing Electron Beam – A cathode-ray tube (CRT) is a large, sealed glass tube.

The apparatus of the experiment incorporated a tube made of glass containing two pieces of metals at the opposite ends which acted as an electrode. The two metal pieces were connected with an external voltage. The pressure of the gas inside the tube was lowered by evacuating the air.

• Apparatus is set up by providing a high voltage source and evacuating the air to maintain the low pressure inside the tube.
• High voltage is passed to the two metal pieces to ionize the air and make it a conductor of electricity.
• The electricity starts flowing as the circuit was complete.
• To identify the constituents of the ray produced by applying a high voltage to the tube, the dipole was set up as an add-on in the experiment.
• The positive pole and negative pole were kept on either side of the discharge ray.
• When the dipoles were applied, the ray was repelled by the negative pole and it was deflected towards the positive pole.
• This was further confirmed by placing the phosphorescent substance at the end of the discharge ray. It glows when hit by a discharge ray. By carefully observing the places where fluorescence was observed, it was noted that the deflections were on the positive side. So the constituents of the discharge tube were negatively charged.

After completing the experiment J.J. Thomson concluded that rays were and are basically negatively charged particles present or moving around in a set of a positive charge. This theory further helped physicists in understanding the structure of an atom . And the significant observation that he made was that the characteristics of cathode rays or electrons did not depend on the material of electrodes or the nature of the gas present in the cathode ray tube. All in all, from all this we learn that the electrons are in fact the basic constituent of all the atoms.

Most of the mass of the atom and all of its positive charge are contained in a small nucleus, called a nucleus. The particle which is positively charged is called a proton. The greater part of an atom’s volume is empty space.

The number of electrons that are dispersed outside the nucleus is the same as the number of positively charged protons in the nucleus. This explains the electrical neutrality of an atom as a whole.

Uses of Cathode Ray Tube

• Used as a most popular television (TV) display.
• X-rays are produced when fast-moving cathode rays are stopped suddenly.
• The screen of a cathode ray oscilloscope, and the monitor of a computer, are coated with fluorescent substances. When the cathode rays fall off the screen pictures are visible on the screen.

Frequently Asked Questions – FAQs

What are cathode ray tubes made of.

The cathode, or the emitter of electrons, is made of a caesium alloy. For many electronic vacuum tube systems, Cesium is used as a cathode, as it releases electrons readily when heated or hit by light.

Where can you find a cathode ray tube?

Cathode rays are streams of electrons observed in vacuum tubes (also called an electron beam or an e-beam). If an evacuated glass tube is fitted with two electrodes and a voltage is applied, it is observed that the glass opposite the negative electrode glows from the electrons emitted from the cathode.

How did JJ Thomson find the electron?

In the year 1897 J.J. Thomson invented the electron by playing with a tube that was Crookes, or cathode ray. He had shown that the cathode rays were charged negatively. Thomson realized that the accepted model of an atom did not account for the particles charged negatively or positively.

What are the properties of cathode rays?

They are formed in an evacuated tube via the negative electrode, or cathode, and move toward the anode. They journey straight and cast sharp shadows. They’ve got strength, and they can do the job. Electric and magnetic fields block them, and they have a negative charge.

What do you mean by cathode?

A device’s anode is the terminal on which current flows in from outside. A device’s cathode is the terminal from which current flows out. By present, we mean the traditional positive moment. Because electrons are charged negatively, positive current flowing in is the same as outflowing electrons.

Who discovered the cathode rays?

Studies of cathode-ray began in 1854 when the vacuum tube was improved by Heinrich Geissler, a glassblower and technical assistant to the German physicist Julius Plücker. In 1858, Plücker discovered cathode rays by sealing two electrodes inside the tube, evacuating the air and forcing it between the electrode’s electric current.

Which gas is used in the cathode ray experiment?

For better results in a cathode tube experiment, an evacuated (low pressure) tube is filled with hydrogen gas that is the lightest gas (maybe the lightest element) on ionization, giving the maximum charge value to the mass ratio (e / m ratio = 1.76 x 10 ^ 11 coulombs per kg).

What is the Colour of the cathode ray?

Cathode-ray tube (CRT), a vacuum tube which produces images when electron beams strike its phosphorescent surface. CRTs can be monochrome (using one electron gun) or coloured (using usually three electron guns to produce red, green, and blue images that render a multicoloured image when combined).

How cathode rays are formed?

Cathode rays come from the cathode because the cathode is charged negatively. So those rays strike and ionize the gas sample inside the container. The electrons that were ejected from gas ionization travel to the anode. These rays are electrons that are actually produced from the gas ionization inside the tube.

What are cathode rays made of?

Thomson showed that cathode rays were composed of a negatively charged particle, previously unknown, which was later named electron. To render an image on a screen, Cathode ray tubes (CRTs) use a focused beam of electrons deflected by electrical or magnetic fields.

For more information about cathode ray experiment, the discovery of electron or other sub-atomic particles, you can download BYJU’S – The learning app. You can also keep visiting the website or subscribe to our YouTube channel for more content.

Put your understanding of this concept to test by answering a few MCQs. Click ‘Start Quiz’ to begin!

Select the correct answer and click on the “Finish” button Check your score and answers at the end of the quiz

Visit BYJU’S for all Chemistry related queries and study materials

Your result is as below

Request OTP on Voice Call

Leave a Comment Cancel reply

Your Mobile number and Email id will not be published. Required fields are marked *

Post My Comment

Register with BYJU'S & Download Free PDFs

Register with byju's & watch live videos.

• Foundations
• Write Paper

Search form

• Experiments
• Anthropology
• Self-Esteem
• Social Anxiety

Cathode Ray Experiment

The electric experiment by j.j. thomson.

J. J. Thomson was one of the great scientists of the 19th century; his inspired and innovative cathode ray experiment greatly contributed to our understanding of the modern world.

This article is a part of the guide:

• Ben Franklin Kite
• Physics Experiments
• Brownian Movement

Browse Full Outline

• 1 Physics Experiments
• 2 Ben Franklin Kite
• 3 Brownian Movement
• 4 Cathode Ray Experiment

Like most scientists of that era, he inspired generations of later physicists, from Einstein to Hawking .

His better-known research proved the existence of negatively charged particles, later called electrons, and earned him a deserved Nobel Prize for physics. This research led to further experiments by Bohr and Rutherford, leading to an understanding of the structure of the atom.

What is a Cathode Ray Tube?

Even without consciously realizing it, most of us are already aware of what a cathode ray tube is.

Look at any glowing neon sign or any ‘old-fashioned’ television set, and you are looking at the modern descendants of the cathode ray tube.

Physicists in the 19th century found out that if they constructed a glass tube with wires inserted in both ends, and pumped out as much of the air as they could, an electric charge passed across the tube from the wires would create a fluorescent glow. This cathode ray also became known as an ‘electron gun’.

Later and improved cathode ray experiments found that certain types of glass produced a fluorescent glow at the positive end of the tube. William Crookes discovered that a tube coated in a fluorescing material at the positive end, would produce a focused ‘dot’ when rays from the electron gun hit it.

With more experimentation, researchers found that the ‘cathode rays’ emitted from the cathode could not move around solid objects and so traveled in straight lines, a property of waves. However, other researchers, notably Crookes, argued that the focused nature of the beam meant that they had to be particles.

Physicists knew that the ray carried a negative charge but were not sure whether the charge could be separated from the ray. They debated whether the rays were waves or particles, as they seemed to exhibit some of the properties of both. In response, J. J. Thomson constructed some elegant experiments to find a definitive and comprehensive answer about the nature of cathode rays.

Thomson’s First Cathode Ray Experiment

Thomson had an inkling that the ‘rays’ emitted from the electron gun were inseparable from the latent charge, and decided to try and prove this by using a magnetic field.

His first experiment was to build a cathode ray tube with a metal cylinder on the end. This cylinder had two slits in it, leading to electrometers, which could measure small electric charges.

He found that by applying a magnetic field across the tube, there was no activity recorded by the electrometers and so the charge had been bent away by the magnet. This proved that the negative charge and the ray were inseparable and intertwined.

Thomson's Cathode Ray Second Experiment

Like all great scientists, he did not stop there, and developed the second stage of the experiment, to prove that the rays carried a negative charge. To prove this hypothesis, he attempted to deflect them with an electric field.

Earlier experiments had failed to back this up, but Thomson thought that the vacuum in the tube was not good enough, and found ways to improve greatly the quality.

For this, he constructed a slightly different cathode ray tube, with a fluorescent coating at one end and a near perfect vacuum. Halfway down the tube were two electric plates, producing a positive anode and a negative cathode, which he hoped would deflect the rays.

As he expected, the rays were deflected by the electric charge, proving beyond doubt that the rays were made up of charged particles carrying a negative charge. This result was a major discovery in itself, but Thomson resolved to understand more about the nature of these particles.

Thomson's Third Experiment

The third experiment was a brilliant piece of scientific deduction and shows how a series of experiments can gradually uncover truths.

Many great scientific discoveries involve performing a series of interconnected experiments, gradually accumulating data and proving a hypothesis .

He decided to try to work out the nature of the particles. They were too small to have their mass or charge calculated directly, but he attempted to deduce this from how much the particles were bent by electrical currents, of varying strengths.

Thomson found out that the charge to mass ratio was so large that the particles either carried a huge charge, or were a thousand times smaller than a hydrogen ion. He decided upon the latter and came up with the idea that the cathode rays were made of particles that emanated from within the atoms themselves, a very bold and innovative idea.

Later Developments

Thomson came up with the initial idea for the structure of the atom, postulating that it consisted of these negatively charged particles swimming in a sea of positive charge. His pupil, Rutherford, developed the idea and came up with the theory that the atom consisted of a positively charged nucleus surrounded by orbiting tiny negative particles, which he called electrons.

Quantum physics has shown things to be a little more complex than this but all quantum physicists owe their legacy to Thomson. Although atoms were known about, as apparently indivisible elementary particles, he was the first to postulate that they had a complicated internal structure.

Thomson's greatest gift to physics was not his experiments, but the next generation of great scientists who studied under him, including Rutherford, Oppenheimer and Aston. These great minds were inspired by him, marking him out as one of the grandfathers of modern physics.

• Psychology 101
• Flags and Countries
• Capitals and Countries

Martyn Shuttleworth (Sep 22, 2008). Cathode Ray Experiment. Retrieved Oct 20, 2024 from Explorable.com: https://explorable.com/cathode-ray-experiment

You Are Allowed To Copy The Text

The text in this article is licensed under the Creative Commons-License Attribution 4.0 International (CC BY 4.0) .

This means you're free to copy, share and adapt any parts (or all) of the text in the article, as long as you give appropriate credit and provide a link/reference to this page.

That is it. You don't need our permission to copy the article; just include a link/reference back to this page. You can use it freely (with some kind of link), and we're also okay with people reprinting in publications like books, blogs, newsletters, course-material, papers, wikipedia and presentations (with clear attribution).

Want to stay up to date? Follow us!

Save this course for later.

Don't have time for it all now? No problem, save it as a course and come back to it later.

Footer bottom

• Privacy Policy

• Subscribe to our RSS Feed
• Like us on Facebook
• Follow us on Twitter

J.J. Thomson’s Cathode Ray Tube Experiment

In 1897, J.J. Thomson conducted a groundbreaking experiment using a cathode ray tube that revolutionized our understanding of atomic structure and subatomic particles . His experiment, conducted at Cambridge’s Cavendish Laboratory, involved manipulating cathode rays with electric and magnetic fields.

Thomson’s custom-made cathode-ray tubes, created by his skilled glassblower assistant Ebenezer Everett, played a crucial role in the success of his experiments. Through his observations, Thomson identified electrons , the first subatomic particles to be discovered, which were found to be 1,000 times smaller than a hydrogen atom.

This experiment provided evidence that cathode rays were composed of tiny particles, rather than waves in the now-rejected ether. It laid the foundation for our understanding of atomic structure and paved the way for advancements in particle physics . The significance of Thomson’s cathode ray tube experiment continues to resonate in the field of science.

Key Takeaways:

• J.J. Thomson conducted a groundbreaking experiment using a cathode ray tube to study electrons and revolutionize our understanding of atomic structure .
• Thomson’s experiments with the cathode ray tube provided evidence that cathode rays were composed of tiny particles, rather than waves in the now-rejected ether.
• His discovery of electrons and the manipulation of cathode rays laid the foundation for our understanding of atomic structure and subatomic particles .
• The quality of the cathode-ray tubes, as well as the skill of the glassblower, were crucial for the success of Thomson’s experiments.
• Thomson’s experiments and subsequent theories inspired generations of physicists and led to further advancements in particle physics .

The Significance of J.J. Thomson’s Cathode Ray Tube Experiment

J.J. Thomson’s cathode ray tube experiment was a groundbreaking achievement that had a profound impact on our understanding of atomic structure and subatomic particles. His experiment provided evidence for the existence of electrons , the first subatomic particles to be discovered. Thomson’s manipulation of cathode rays and observations of their movement and behavior allowed him to determine the charge-to-mass ratio of electrons.

This experiment led Thomson to propose his “plum pudding” model of the atom, which suggested that atoms consisted of a positively charged “pudding” with negatively charged electrons embedded within it. Thomson’s experiment and subsequent theories about the nature of cathode rays and electrons paved the way for further advancements in particle physics and the development of the modern atomic model.

Thomson’s work inspired future physicists such as Ernest Rutherford and his famous gold foil experiment, which further elucidated the structure of the atom and led to the development of quantum physics. Thomson’s discovery of electrons and his contributions to modern physics solidify his place as one of the pioneers in the field.

“Thomson’s cathode ray tube experiment revolutionized our understanding of atomic structure and subatomic particles. His discovery of the charge-to-mass ratio of electrons laid the foundation for future advancements in the field of particle physics.” – Dr. Emily Johnson, Physics Professor

The Influence on Future Physicists

J.J. Thomson’s cathode ray tube experiment not only advanced our knowledge of atomic structure but also inspired future generations of physicists. His groundbreaking research and discoveries opened up new avenues of exploration within the field of particle physics and shaped the trajectory of scientific advancements.

Thomson’s experiment provided a solid foundation for further studies on the nature of electrons and subatomic particles. The understanding gained from his experiment led to the development of new theories and models that continue to be explored and refined by physicists to this day.

His contributions to the field of particle physics revolutionized our understanding of the microscopic world and set the stage for groundbreaking discoveries in the years to come. Without Thomson’s cathode ray tube experiment, our knowledge of atomic structure and subatomic particles would be vastly different, and the field of particle physics may not have progressed to the extent it has.

Contributions to Modern Physics

J.J. Thomson’s cathode ray tube experiment made significant contributions to modern physics . His discovery of electrons and the understanding of their charge-to-mass ratio laid the groundwork for further advancements in the field.

Thomson’s experiment and subsequent theories about the nature of cathode rays and electrons influenced the development of the modern atomic model, which has been refined and expanded upon over the years. His work paved the way for the development of quantum physics and the exploration of the fundamental building blocks of matter.

Thomson’s legacy as one of the pioneers of modern physics is evident in the continued study of particle physics and the development of new technologies based on his discoveries. His cathode ray tube experiment remains a cornerstone of scientific exploration and a testament to the importance of curiosity and experimentation in advancing our understanding of the universe.

Applications and Legacy of J.J. Thomson’s Cathode Ray Tube Experiment

The cathode ray tube experiment conducted by J.J. Thomson not only revolutionized our understanding of atomic structure and subatomic particles but also had a significant impact beyond the realm of scientific research.

One of the key applications of cathode ray tubes stemming from Thomson’s experiment is in television technology . These cathode ray tubes served as the display screens for early television sets, playing a crucial role in the development of this transformative technology.

Furthermore, cathode ray tubes found their use in oscilloscopes . These devices are essential for visualizing and measuring electrical waveforms, making them invaluable in various scientific and engineering fields.

Thomson’s pioneering work on the discovery of electrons and the development of the cathode ray tube also led to a groundbreaking advancement in medical imaging. By stopping fast-moving cathode rays, X-rays could be produced, enabling medical professionals to visualize internal structures and diagnose conditions accurately.

Recognizing the significance of his contributions, J.J. Thomson was awarded the Nobel Prize in Physics in 1906. This prestigious accolade serves as a testament to the profound impact his experiments had on the field of particle physics and the advancement of scientific knowledge.

Thomson’s cathode ray tube experiment and subsequent discoveries continue to inspire and influence future generations of scientists. His legacy is apparent in the continued study of particle physics and the development of new technologies based on his groundbreaking experiments and theories.

What was J.J. Thomson’s Cathode Ray Tube Experiment?

J.J. Thomson conducted a groundbreaking experiment using a cathode ray tube to study electrons and revolutionize our understanding of atomic structure.

When and where did the experiment take place?

The experiment took place in 1897 at Cambridge’s Cavendish Laboratory, where Thomson spent his scientific career.

How did Thomson manipulate the cathode rays?

Thomson was able to manipulate the cathode rays using electric and magnetic fields.

What did Thomson discover through his experiments?

Thomson was able to identify electrons, the first subatomic particles to be discovered, which were 1,000 times smaller than a hydrogen atom.

What evidence did Thomson’s experiments provide about cathode rays?

Thomson’s experiments provided evidence that cathode rays were composed of tiny particles, rather than waves in the now-rejected ether.

What was the significance of Thomson’s discovery of electrons?

Thomson’s discovery of electrons and the manipulation of cathode rays laid the foundation for our understanding of atomic structure and subatomic particles.

What was Thomson’s proposed model of the atom?

Thomson proposed the “plum pudding” model of the atom, which suggested that atoms consisted of a positively charged “pudding” with negatively charged electrons embedded within it.

What applications did cathode ray tubes have beyond scientific research?

Cathode ray tubes became integral parts of television technology , oscilloscopes , and also revolutionized medical imaging through the production of X-rays.

What was J.J. Thomson’s legacy in the field of particle physics?

Thomson’s work on the discovery of electrons and his profound impact on the field earned him the Nobel Prize in Physics in 1906, inspiring future scientists and advancing our understanding of subatomic particles and atomic structure.

• X (Twitter)

Similar Posts

Fritz strassmann contributions to the periodic table.

I am excited to share with you the remarkable contributions of Fritz Strassmann to the periodic…

Mendeleev Contributions to the Periodic Table: Revolutionizing Our Understanding of Chemical Elements

Mendeleev Contributions to the Periodic Table: Revolutionizing Our Understanding of Chemical Elements Dmitri Mendeleev, a Russian…

Charles Janet’s Contributions to the Periodic Table

Charles Janet, a French engineer, company director, inventor, and biologist, made significant contributions to the periodic…

How To Use Electron Configuration

Understanding electron configuration is essential for comprehending the energy and shape of an atom’s orbitals. By…

Electron Configuration For Indium

Welcome to our article on the electron configuration for indium. In this section, we will explore…

Edward Frankland Contributions to the Periodic Table

Edward Frankland, a renowned chemist born in 1825 in Lancashire, England, made significant contributions to the…

• More Networks

• Chemistry Class 9 Notes
• Physical Chemistry
• Organic Chemistry
• Inorganic Chemistry
• Analytical Chemistry
• Biochemistry
• Chemical Elements
• Chemical Compounds
• Chemical Formula
• Real life Application of Chemistry
• Chemistry Class 8 Notes
• Chemistry Class 10 Notes
• Chemistry Class 11 Notes
• Chemistry Class 12 Notes

Cathode Ray Experiment

Cathode Ray Experiment , also known as the Crookes tube experiment , is a historically significant experiment in the field of physics that helped scientists understand the nature of electrons. English scientist Sir J.J. Thomson performed an experiment using a Cathode Ray Tube, which led to the discovery of an electron.

In this article, we will discuss this significant experiment, including details of the Cathode Ray Tube, the procedure of the experiment, and J.J. Thomson’s observations, which led to one of the greatest discoveries in the field of science.

Table of Content

• What is the Cathode Ray Experiment?

What is Cathode Ray Tube (CRT)?

• Experiment Setup

Applications of Cathode Ray Experiment

• Limitations of the Cathode Ray Experiment

What is Cathode Ray Experiment?

Cathode Ray Experiment, also known as the Cathode Ray Tube (CRT) Experiment, is a fundamental experiment in the history of physics that played a crucial role in understanding the nature of electrons and contributed to the development of modern electronics and television technology.

The experiment was first conducted by Sir William Crookes in the 1870s and later improved upon by scientists like J.J. Thomson in the late 19 th and early 20 th centuries.

Who is J.J. Thomson?

Joseph John Thomson, often called J.J. Thomson, was a British physicist celebrated for winning the Nobel Prize in Physics in 1906 for his research on how electricity moves through gases. His notable achievement was the discovery of the electron during the Cathode Ray Experiment.

A Cathode Ray Tube (CRT) is a special glass tube that played a big part in J.J. Thomson’s important experiment. This clever device helped scientists understand tiny particles that make up atoms.

Structure of CRT

CRT has a simple structure. It’s a sealed glass tube with two electrodes at each end – one is called the cathode (negative), and the other is the anode (positive). When these electrodes are connected to power, they create an electric field inside the tube. The tube is made empty, like a vacuum, so there’s no air inside.

The vacuum is essential because it lets cathode rays move in a straight line from the cathode to the anode without any interference from air. This controlled setup helps scientists study the behavior of cathode rays in different situations. The CRT is a key tool that led to important discoveries about the tiniest building blocks of matter.

Cathode Ray Experiment Setup

Below is the detailed setup for the Cathode Ray Tube Experiment with the elements used along with the diagram:

• Cathode Ray Tube (CRT): A sealed glass tube with a cathode and anode at either end.
• Cathode: A negatively charged electrode inside the CRT.
• Anode: A positively charged electrode inside the CRT.
• High Voltage Generator: A power supply capable of providing a high voltage between the cathode and anode.
• Vacuum Pump: A pump to evacuate air from the CRT to create a low-pressure environment.
• Discharge Tube: The entire CRT assembly including the cathode, anode, and vacuum space.
• Perforated Anode Disk: Placed at the anode end to allow some cathode rays to pass through.

Procedure of Experiment

Below is the procedure steps for the experiment with the perspective of the JJ Thomson:

• JJ Thomson created a sealed cathode ray tube with minimal air inside.
• Connected the tube to a power source, causing electrons (cathode rays) to shoot out.
• Observed electrons moving in straight lines inside the vacuum of the tube.
• Introduced an electric field by adjusting the power, causing electrons to change their path.
• Experimented with magnets, observing electrons being affected and swerving in response.
• Adjusted power settings to observe changes in electron movement, establishing consistent patterns.
• Systematically recorded electron behavior in various situations.
• Determined the charge-to-size ratio of electrons, making a significant discovery.
• Concluded that cathode rays were composed of tiny particles known as electrons.
• Thomson’s discovery revolutionized understanding of the microscopic world’s building blocks.

Observation of Cathode Ray Experiment

In the Cathode Ray Experiment, J.J. Thomson made a ground breaking observation i.e., when cathode rays encountered electric and magnetic fields, they exhibited intriguing behavior. Thomson noticed their deflection, and the direction of this deflection pointed to a negative charge. This pivotal observation led Thomson to the groundbreaking conclusion that cathode rays were composed of negatively charged particles, now recognized as electrons.

Conclusion of Cathode Ray Experiment

Cathode Ray Experiment marked a revolutionary moment in the realm of science. J.J. Thomson’s demonstration of cathode ray deflection and the identification of these rays as negatively charged particles conclusively affirmed the existence of subatomic particles. This groundbreaking experiment transformed our comprehension of atomic structure, shattering the notion that atoms were indivisible. Instead, Thomson’s work revealed the presence of smaller components within atoms. This pivotal episode in the history of physics not only altered fundamental perspectives but also laid the foundation for subsequent advancements in the field.

The Cathode Ray Experiment, conducted by Sir J.J. Thomson in 1897, led to several significant applications and advancements in various fields:

• Discovery of the Electron: The most direct outcome of the Cathode Ray Experiment was the discovery of the electron, a fundamental component of atoms. This discovery was pivotal in the development of atomic theory and quantum physics.
• Television and Computer Monitors: The technology behind cathode ray tubes (CRTs) was essential in the development of early television and computer monitors. These devices used electron beams, controlled and focused by magnetic or electric fields, to illuminate phosphors on the screen, creating images.
• Medical Imaging: Cathode ray technology found applications in medical imaging, particularly in early forms of X-ray machines and later in more advanced imaging technologies.
• Electron Microscopy: The principles discovered in the Cathode Ray Experiment were integral to the development of electron microscopy, which uses a beam of electrons to create an image of a specimen. This technology allows for much higher resolution than traditional light microscopy.

Limitations of Cathode Ray Experiment

The Cathode Ray Experiment, while groundbreaking in its time, had several limitations:

• Lack of Precise Measurement Tools: At the time of Thomson’s experiments, the precision and accuracy of measurement tools were limited. This meant that the measurements of the charge-to-mass ratio of electrons were not as accurate as what can be achieved with modern equipment.
• Incomplete Understanding of Subatomic Particles: Thomson’s experiment was conducted at a time when the structure of the atom was not fully understood. This meant that while the experiment led to the discovery of the electron, it did not provide a complete picture of subatomic particles and their interactions.
• Limited Control over Experimental Conditions: The vacuum technology and methods to control the electric and magnetic fields in Thomson’s time were rudimentary compared to today’s standards. This limited the ability to control experimental conditions precisely.
• Atomic Structure
• Discovery of Electrons

Cathode Ray Experiment – FAQs

J.J. Thomson, whose full name is Joseph John Thomson, was a British physicist born on December 18, 1856, in Cheetham Hill, Manchester, England, and he passed away on August 30, 1940. He is best known for his discovery of the electron, a fundamental subatomic particle.

What are Cathode Rays?

Cathode rays are streams of electrons observed in a vacuum when a high voltage is applied between electrodes in a cathode ray tube (CRT). These rays were first discovered and studied by J.J. Thomson in the late 19th century.

What was the Cathode Ray Experiment?

The cathode ray experiment, conducted by J.J. Thomson in the late 19th century, was a series of experiments that led to the discovery of electrons and provided crucial insights into the nature of subatomic particles.

What are Two Conclusions of the Cathode Ray Experiment?

Two conclusion of Cathode Ray Experiment are: Cathode rays are streams of negatively charged particles (electrons). These particles are fundamental components of all atoms.

Why did J.J. Thomson Experimented with Cathode?

J.J. Thomson experimented with cathode rays to investigate their nature and to understand the internal structure of atoms.

Similar Reads

• School Chemistry
• Geeks Premier League
• Geeks Premier League 2023
• Chemistry-Class-9
• Physical-Chemistry

Please Login to comment...

Improve your coding skills with practice.

What kind of Experience do you want to share?

• Why Does Water Expand When It Freezes
• Gold Foil Experiment
• Faraday Cage
• Oil Drop Experiment
• Magnetic Monopole
• Why Do Fireflies Light Up
• Types of Blood Cells With Their Structure, and Functions
• The Main Parts of a Plant With Their Functions
• Parts of a Flower With Their Structure and Functions
• Parts of a Leaf With Their Structure and Functions
• Why Does Ice Float on Water
• Why Does Oil Float on Water
• How Do Clouds Form
• What Causes Lightning
• How are Diamonds Made
• Types of Meteorites
• Types of Volcanoes
• Types of Rocks

Cathode Ray Tube (CRT)

Cathode ray tube definition.

A cathode ray tube or CRT is a device that produces cathode rays in a vacuum tube and accelerates them through a magnetic and electric field to strike a fluorescent screen to form images.

Cathode Ray Tube History

The eminent physicist Johann Hittorf discovered cathode rays in 1869 in Crookes tubes. Crookes tubes are partially vacuum tubes having two electrodes kept at a high potential difference to discharge cathode rays from the negatively charged electrode cathode. Arthur Schuster and William Crooks proved that cathode rays are deflected by electric and magnetic fields, respectively. In the year 1897, the English physicist J.J. Thomson’s experiments with cathode rays led to the discovery of the electron , the first subatomic particle to be discovered.

The earliest version of the cathode ray tube, Braun Tube, was invented in 1897 by the German physicist Ferdinand Braun. It employed a cold cathode for working. He used a phosphor-coated mica screen and a diaphragm to produce a visible dot. The cathode beam was deflected by a magnetic field only, in contrast to the discharge tube used earlier in the same year by J.J. Thomson, which employed only electrostatic deflection using two internal plates. Braun is also credited with the invention of the cathode ray tube oscilloscope, also known as Braun’s Electrometer.

In 1907, the cathode ray tube was first used in television when Russian scientist Boris Rosing passed a video signal through it to obtain geometric shapes on the screen. Earlier cathode ray tubes used cold cathodes. However, a hot cathode came into existence after being developed by John B. Johnson and Harry Weiner Weinhart of Western Electric. This type of cathode consists of a thin filament heated to a very high temperature by passing an electric current through it. It uses thermionic emissions in vacuum tubes to release electrons from a target.

The first commercial cathode ray tube television manufacture dates back to 1934 by the company Telefunken in Germany. This curved the path for large-scale manufacture and use of CRT TVs until the recent development of Liquid Crystal Displays, Light Emitting diodes, and Plasma TVs.

Cathode Ray Tube Description

The CRT is composed of three parts.

Electron Gun

This part produces a stream of electrons traveling at very high speeds by the process of thermionic emission. A thin filament is heated up by the passage of alternating current through it. It is used to heat the cathode, generally made of the metal cesium, which releases a stream of electrons when heated to temperatures of about 1750 F. The anode, which is the positively charged electrode, is placed a small distance away and is maintained at a high voltage which forces the cathode rays to gain considerably high accelerations as they move towards it.

The stream of electrons passes through a small aperture in the anode to land in the central part of the tube. There is a grid or a series of grids maintained at a variable potential, which control(s) the intensity of the electron beam reaching the anode. The brightness of the final image formed on the screen is also restricted thus. A monochrome CRT has a single electron gun, whereas a color CRT has three electron guns for the primary colors, red, green, and blue, which overlap among themselves to produce colored images.

Deflection System

The electron stream, after coming out of the anode, tends to spread out in the form of a cone. But it needs to be focused to form a sharp point on the screen. Also, its position on the screen should be as desired. This is achieved by subjecting the beam to magnetic and electric fields perpendicular to each other. The straight path of the beam then gets deflected, and it hits the screen at the desired point. It should be kept in mind that the anode gives it a considerable acceleration of the order of fractions of the speed of light. This endows the beam with very high amounts of energy.

Fluorescent CRT Screen

This part projects the image for the user’s view. It is given a coating of zinc sulfide or phosphorus which can produce fluorescence. When the highly energetic beam of electrons strikes it, its kinetic energy is converted to light energy, thus forming an illuminated spot on the screen. When complex signals are applied to the deflection system, the bright spot races across the screen horizontally and vertically, forming what is called the raster.

The raster scanning takes place in the same way as we would read a book. That is, from left to right, then go down and back to the left and move right to finish reading the line. This continues until the full screen is finished scanning. However, the CRT scan takes place so rapidly every second that the viewer cannot follow the actual movement of the dot but can see the whole image so produced.

Cathode Ray Tube Mechanism Video

Cathode ray tube experiment by j.j.thomson.

It was already known to the scientific fraternity that cathode rays were capable of depositing a charge, thereby proving them to be the carriers of some kind of charge. But they were not really sure whether this charge could be separated from the particles forming the rays. Hence, the celebrated English physicist J. J. Thomson devised an experiment to test the exact nature.

Thomson’s First CRT Experiment

Thomson took a cathode ray tube, and at the place where the electron beam was supposed to strike, he positioned a pair of metal cylinders having slits on them. The pair, in turn, was connected to an electrometer, a device for catching and measuring electric charges. Then, on operating the CRT, in the absence of any electric or magnetic fields, the beam of electrons traveled straight up to the cylinders, passed through the aptly positioned slits, and made the electrometer register a high amount of charge.  So far, the result was quite an expected one.

In the next step, he put a magnet in the vicinity of the cathode ray path that set up a magnetic field. Now, as you may know, an electric field and a magnetic field can never act along the same line. Hence, the charged cathode rays get deflected from their path and give the slits a miss. The electrometer, hence, fails to register anything whatsoever. Thus, he concluded the cathode rays carry the charges along with them wherever they go, and it is impossible to separate the charges from the rays.

Thomson’s Second CRT Experiment

In his second attempt, Thomson tried to deflect the cathode rays by applying an electric field. It could prove the nature of the charge carried by them. There had been attempts before to achieve the end, but they had failed. He thought that if the streams are electrically charged, then they should be deflected by electric fields, but he could not explain why his setup failed to show any such movement.

He later came up with the idea that there was no change from the original path as the stream was covered by a conductor, that is, a layer of ionized air in this case. So he took great pains to make the interior of the tube as close to a vacuum as he could by drawing out all the residual air, and bravo! There was a pronounced deflection in the cathode rays. The great scientist had cleverly put two electrodes, positive and negative, halfway down the tube to produce the electric field. On observing that the beam deflected towards the anode, he could successfully prove that the cathode rays carried one and only one type of charge, negative.

Thomson’s Third CRT Experiment

Thomson tried to calculate the charge-to-mass ratio of the particles constituting the rays and found it to be exceptionally small. That implies the particles have either a very small mass or a very high charge. He decided on the former and gave a bold hypothesis that cathode rays were formed of particles emanating from the atom itself.

Experiment Summary

By using certain modifications in the regular CRT, Thomson’s cathode ray tube experiment proved that cathode rays consist of streams of negatively charged particles having smaller masses than that atoms. It was highly likely for them to be one of the components of atoms.

Cathode Ray Tube Applications

Oscilloscope.

It measures the changes in electrical voltage with time. If the horizontal plate is attached to a voltage source and the vertical to a clocking mechanism, then the variations in the magnitude of the voltage will show up on the CRT monitor in the form of a wave. With an increase in voltage, the line forming the wave shoots up while it comes down if the voltage is low. If, instead of a variable voltage source, the horizontal plates are connected to a circuit, then the arrangement can be used to detect any sudden change in its voltage. Thus, it can be used for troubleshooting purposes.

Televisions

Before the emergence of lightweight LCD and plasma TVs, all televisions were bulky and had cathode ray tubes in them. They had a very fast raster scan rate of about 1/50 th of a second. In a color TV, the persistence of the different colors would last for only the time between two consecutive scans. If it stayed longer, then the tube would produce blurred images. But if the effect of the colors ended before the next scan, then it gave rise to a flickering screen. Modern tube TVs use flat-screen CRTs, unlike their yesteryear counterparts.

Cathode Ray Tube Amusement Device

The predecessor to modern video games, the cathode ray tube amusement device gave the world the first gaming device. The CRT produced electronic signals in the form of a ray of light. Controller knobs in the tube were then used to adjust the trajectories of light so that it could hit on a target imprinted on a clear overlay attached to the CRT display screen. The game was conceptualized on World War II missile displays and created the effect of firing missiles at targets.

Other Applications

Cathode ray tube monitors are widely used as display devices in radars. However, the CRT computer monitor has gradually become obsolete with the introduction of TFT-LCD thin panel monitors.

Health Risks

Ionizing Radiation :  CRTs can emit a small amount of ionizing radiation that needs to be kept under control by the Food and Drug Administration Regulations in 21 C.F.R. 1020.10. However, most CRTs manufactured after 2007 have much lesser emissions than the prescribed limit.

Flicker:  Low refresh rates, 60Hz and below, can produce flicker in most people, although the susceptibility of eyesight to flicker varies from person to person.

Toxicity: Modern-day CRTs may have their rear glass tubes made of leaded glass, which is difficult to dispose of as they can cause an environmental hazard. Some of the older versions also contain cadmium and phosphorus, making the tubes highly toxic. Special cathode ray tube recycling processes fulfilling the norms of the United States Environmental Protection Agency should be followed.

Implosion: Very high levels of vacuum inside a CRT can cause it to implode if there is any damage to the covering glass. This is caused by the high atmospheric pressure, which forces the glass to crack and fly off at high speeds in all directions. Though modern CRTs have strong envelopes to prevent shattering, they should be handled very carefully.

Noise: The signal frequencies used to operate CRTs are of a very high range and are usually imperceptible to the human ear. However, small children can sometimes hear very high-pitched noises near CRT televisions. That is because they have a greater sensitivity to hearing.

The cathode ray tube was a useful invention in Science for the discovery of an important fundamental particle like an electron and also opened up newer arenas of research in atomic Physics. Until about the year 2000, it was the mainstay of televisions all over the world before being forced into oblivion due to the emergence of newer technologies.

https://en.wikipedia.org/wiki/Cathode_ray

https://www.chemteam.info/AtomicStructure/Disc-of-Electron-History.html

https://www.techtarget.com/whatis/definition/cathode-ray-tube-CRT

https://explorable.com/cathode-ray-experiment

http://www.scienceclarified.com/Ca-Ch/Cathode-Ray-Tube.html

Article was last reviewed on Tuesday, May 9, 2023

Related articles

One response to “Cathode Ray Tube (CRT)”

I want to ask that in cathode ray tube tv why electrons are never finish which is on cathode while the material have limited electrons

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Save my name, email, and website in this browser for the next time I comment.

Popular Articles

Join our Newsletter

Fill your E-mail Address

Related Worksheets

• Privacy Policy

© 2024 ( Science Facts ). All rights reserved. Reproduction in whole or in part without permission is prohibited.

• Scientific Biographies

Joseph John “J. J.” Thomson

In 1897 Thomson discovered the electron and then went on to propose a model for the structure of the atom. His work also led to the invention of the mass spectrograph.

The British physicist Joseph John “J. J.” Thomson (1856–1940) performed a series of experiments in 1897 designed to study the nature of electric discharge in a high-vacuum cathode-ray tube, an area being investigated by many scientists at the time.

Thomson interpreted the deflection of the rays by electrically charged plates and magnets as evidence of “bodies much smaller than atoms” (electrons) that he calculated as having a very large value for the charge-to-mass ratio. Later he estimated the value of the charge itself.

Structure of the Atom and Mass Spectrography

In 1904 Thomson suggested a model of the atom as a sphere of positive matter in which electrons are positioned by electrostatic forces. His efforts to estimate the number of electrons in an atom from measurements of the scattering of light, X, beta, and gamma rays initiated the research trajectory along which his student Ernest Rutherford moved.

Thomson’s last important experimental program focused on determining the nature of positively charged particles. Here his techniques led to the development of the mass spectrograph. His assistant, Francis Aston, developed Thomson’s instrument further and with the improved version was able to discover isotopes—atoms of the same element with different atomic weights—in a large number of nonradioactive elements.

Early Life and Education

Ironically, Thomson—great scientist and physics mentor—became a physicist by default. His father intended him to be an engineer, which in those days required an apprenticeship, but his family could not raise the necessary fee. Instead young Thomson attended Owens College, Manchester, which had an excellent science faculty. He was then recommended to Trinity College, Cambridge, where he became a mathematical physicist.

In 1884 he was named to the prestigious Cavendish Professorship of Experimental Physics at Cambridge, although he had personally done very little experimental work. Even though he was clumsy with his hands, he had a genius for designing apparatus and diagnosing its problems. He was a good lecturer, encouraged his students, and devoted considerable attention to the wider problems of science teaching at university and secondary levels.

Ties to the Chemical Community

Of all the physicists associated with determining the structure of the atom, Thomson remained most closely aligned to the chemical community. His nonmathematical atomic theory—unlike early quantum theory—could also be used to account for chemical bonding and molecular structure (see Gilbert Newton Lewis and Irving Langmuir ). In 1913 Thomson published an influential monograph urging chemists to use the mass spectrograph in their analyses.

A Nobel Prize

Thomson received various honors, including the Nobel Prize in Physics in 1906 and a knighthood in 1908. He also had the great pleasure of seeing several of his close associates receive their own Nobel Prizes, including Rutherford in chemistry (1908) and Aston in chemistry (1922).

Featured image: Science History Institute

Browse more biographies

Søren Sørensen

Susan Solomon

Frederick Grant Banting

Copy the above HTML to republish this content. We have formatted the material to follow our guidelines, which include our credit requirements. Please review our full list of guidelines for more information. By republishing this content, you agree to our republication requirements.

Talk to our experts

1800-120-456-456

• Cathode Ray Experiment

What are Cathode Rays?

Cathode rays are a beam of negatively charged electrons traveling from the negative end of an electrode to the positive end within a vacuum, across a potential difference between the electrodes.

How Do the Cathode Rays Work?

The cathode is a negative electrode, Anode is the positive electrode. Since electrons are repelled by the negative electrode, the cathode is the source of cathode rays inside a vacuum environment. When a potential difference is applied, the electrons jump to an excited state and travel at high speeds to jump back-and-forth inside the vacuum glass chamber and when some cathode rays certain molecules of the cathode screen, they emit light energy. A wire is connected from anode to cathode to complete the electrical circuit.

Construction of a Cathode Ray Tube

Its Basic Components are: -

Electron Gun Assembly: - It is the source of the electron beams. The electron gun has a heater, cathode, pre-accelerating anode, focusing anode and accelerating anode.

Deflecting Plates: - They produce a uniform electrostatic field only in one direction, and accelerate particles in only one direction.

Screen: - The inner layer of the screen is coated with phosphorus, and produces fluorescence when cathode rays hit the screen by a process of phosphorus excitation.

Aquadag: - It is an aqueous solution of graphite used to collect the secondary emitted electrons which are required to keep the cathode ray in electrical equilibrium.

What is the Cathode Ray Tube Experiment?

In 1897, great physician J.J. Thompson, conducted his first cathode ray tube experiment to prove that rays emitted from an electron gun are inseparable from the latent charge. He built his cathode ray tube with a metal cylinder on the other end. The metal had two small diversions(slits), leading to an electrometer that could measure a small electric charge. From the first experiment, he discovered that the electrometers stopped measuring electric charge. From this, he deduced that the electric charge and the cathode rays must be combined and are the same entity.

Then he conducted a Second experiment, to prove the charge carried by the cathode rays was negative or positive. Now, he put a negatively charged metal plate on one side of the cathode rays to go past the anode, and a positively charged metal plate on the other side. Instead of an electrometer at one end of the Cathode Ray Tube, he used a fluorescent coated tube that would glow where the cathode ray hit it. When the charged metal plates were introduced he found that the cathode rays bent away from the negative plate and towards the positive plate. This proved that the cathode rays were negatively charged.

Then he performed the third experiment, to know the nature of the particles and reduce the mass of the particles as they had too small of a mass to be calculated directly. For the experiment, he used the cathode ray tube and with a high applied potential difference between the two electrodes, with the negatively charged cathode producing the cathode rays. He had already deduced that the particles were negatively charged. Firstly, he applied an electric field in the path between anode and cathode and measured the deflections from the straight path. Now he applied a magnetic field across the cathode ray tube by using an external magnetic field. The cathode ray is deflected by the magnetic field. Now he changed the direction of the external magnetic field and found that the beam of electrons is deflected in the opposite direction. From this experiment, he concluded that the electrostatic deflection is the same as the electromagnetic deflection for the cathode rays and he was able to calculate the charge to mass ratio of the electron.

After these three experiments, he deduced that inside the atom there consist of a subatomic particle, originally named ‘corpuscle’, then changed to ‘electron’ which is 1800 times lighter than the mass of hydrogen atom (Lightest atom).

Formula Used

The derivation of the formula used to calculate the charge to the mass ratio:

For Electric Field the force on a particle is

Force(F)=Charge(Q)*Electric field(E) ---<1>

For Magnetic Field the force on a particle moving with velocity is:

F=q*velocity(v)*Magnetic Field(B) ---<2>

From 1 and 2 we get,

V=E/B ----<3>

From the definition of Force,

Acceleration(a)= Force(f)/mass(m) ----<4>

Combining 1 and 4

a=q*E/m ----<5>

From Newton’s law Of motion, vertical displacement is:

Y= (1/2)*a*t*t ----<6>

From 5 and 6

q/m=(2*y*v*v)/x*x*E

Cathode Ray Tubes (CRT) 

The cathode ray tube (CRT) is a vacuum tube, in which electrons are discharged from the cathode and accelerated through a voltage, and thereby gains acceleration of some 600 km/s for every volt. These accelerated electrons collide into the gas inside the tube, thereby allowing it to glow. This enables us to see the path of the beam. Helmholtz coil, a device for producing a region of nearly uniform magnetic field, is also used to apply a quantifiable magnetic field by passing a current through them.

A magnetic field will cause a force to act on the electrons which are perpendicular to both the magnetic field and their direction of travel. Thus, a circular path will be followed by a charged particle in a magnetic field. The faster the speed of a charged particle in a magnetic field, the larger the circle traced out in a magnetic field. Contrarily, the larger the magnetic field needed for a given radius of curvature of the beam. The paths of the electrons are distorted by the magnet in CRT Tv when they are brought near the screen. The picture on the screen appears when the electrons accurately hit phosphors on the back of the screen. Because of this, different colors of light are emitted on the screen when the electrons are impacted. Hence, the electrons are forced to settle in the wrong place, thereby causing the distortion of the image and the psychedelic colors.

Postulates of J.J. Thomson’s Atomic Model

After the Cathode ray tube experiment, Thomson gave one of the first atomic models including the newly discovered particle. 

His model stated: -

An atom resembles a sphere of positive charge with a negative charge present inside the sphere.

The positive charge and the negative charge were equal in magnitude and thus the atom had no charge as a whole and is electrically neutral.

His model resembles a plum pudding or watermelon. It assumed that positive and negative charge inside an atom is randomly spread across the whole sphere like the red part of the watermelon (positive charge) and the black seeds (negative charge).

Practical Uses of Cathode Ray Tube Experiment

In ancient times, the cathode ray tubes were used in the beam where the electron was considered with no inertia but have higher frequencies and can be made visible for a short time.

Many scientists were trying to get the secrets of cathode rays, while others were in search of the practical uses or applications of cathode ray tube experiments. And the first search was ended and released in 1897 which was introduced as Karl Ferdinand Braun’s oscilloscope. It was used for producing luminescence on a chemical affected screen in which cathode rays were allowed to pass through the narrow aperture by focusing into the beams that looked like a dot. This dot was passed for scanning across the screen which was represented visually by the electrical pulse generator. 

Then during the first two to three decades of the twentieth century, inventors continued to search the uses of cathode ray tube technology. Then inspired by Braun's oscilloscope, A. A. Campbell advised that a cathode ray tube would be used for projecting video images on the screen. But, this technology of the time did not get matched with the vision of Campbell-Swinton. It was only until 1922, when Philo T. Farnsworth developed a magnet to get focused on the stream of electrons on the screen, for producing the image. Thus, the first kind of it, Farnsworth, was quickly backed up by Zworykin’s kinescope, known as the ancestor of modern TV sets.

Nowadays, most image viewer devices are made with the help of cathode ray tube technology including the guns of electrons which are used in huge areas of science as well as medical applications. One such use for cathode-ray tube research is the microscope invented by Ernst Ruska in 1928. The microscope based on electrons uses the stream of electrons to magnify the image as the electrons have a small wavelength which is used for magnifying the objects which are very small to get resolved by visible light. Just like Plucker and Crookes work, Ernst Ruska used a strong field of magnetic lines for getting it focused on the stream of electrons into an image.

Solved Example:  

Question: The charge of an electron e=1.602∗10−19 and its is mass m=9.11∗10−31. The stopping potential of an electron traveling in a cathode ray tube is V=5V. Find the velocity of an electron traveling (where charge of an electron e=1.602∗10−19 and mass m=9.11810−31).

Answer: Here we need to find the velocity of traveling electrons using the given stopping potential.

We know that eV=12mv2, the charge(e) and mass(m) of the electron is also given as,

e=1.602∗10−19 and m=9.11∗10−31

By substituting the values of e, m, V.(1.602∗10−19)(5)

=12(9.11∗10−31)(v2)v2

=(1.602∗10−19)(5)(2)9.11∗10−31v

=1.33∗106m/s             

FAQs on Cathode Ray Experiment

1. What is the procedure of the Cathode Ray Experiment?

The apparatus of Cathode Ray Experiment is arranged in such a way that the terminals have high voltage with the internal pressure, which is reduced by removing the air inside the CRT. Because of the high voltage in the terminal,  the partial air inside it is ionized and hence gas becomes the conductor. The electric current propagates as a closed-loop circuit. In order to recognize and measure the ray produced, a dipole is set up. The cathode rays will begin deflecting and repel from the dipole and move towards the anode because of the dipole. The phosphorescent substance is arranged in such a way that the rays strike the substance. And hence, it causes small sparks of light, which detects the stream of rays.

2. What are Cathode ray tubes?

Cathode ray tubes (CRT) are a presentation screen that produces pictures as a video signal. Cathode ray tubes (CRT) is a type of vacuum tube that displays pictures when electron beams from an electron gun hit a luminous surface. The CRT produces electron beams, accelerates them at high speed, and thereby deflecting them to take pictures on a phosphor screen. Electronic presentation gadgets being the most established and least expensive electronic presentation innovation, were initially made with CRTs. CRTs work at any aspect ratio, at any resolution, and geometry without the need to resize the picture. CRTs work on the principle of an optical and electromagnetic phenomenon, called cathodoluminescence.

3. What are the applications of Cathode ray tubes?

The following are the applications of Cathode ray tubes.

The main components of a cathode ray tube (CRT) includes A Vacuum tube holding an electron cannon and a screen lined with phosphors.

The technology of Cathode ray tubes is used by Televisions and computer monitors. Three electron cannons correlate to corresponding types of phosphors in color CRTs, one for each main color viz red, green, and blue.

Ancient computer terminals and black and white televisions are examples of monochromatic CRTs.

cathode ray tube (CRT) is also used in oscilloscopes, which are machines that display and analyze the waveform of electronic signals.

A cathode ray amusement device was the very first video game to be produced, which were used in old military radar screens.

4. What are the basic principles of the CRT?

There are three basic principles of the CRT as the following:

Electrons are released into a vacuum tube from very hot metal plates.

The released electrons are accelerated and their direction of movement is controlled by using either a magnetic field from a coil that is carrying an electric current or by a voltage between metal plates.

A high-velocity beam of electrons hits some materials such as zinc sulfide. The spot is created on the fluorescent screen, and it causes material, called a phosphor, to glow, giving a spot of light as wide as the beam.

5.  How to understand the concept of the Cathode Ray Experiment easily?

Students can understand the concept of the Cathode Ray Experiment easily with the help of a detailed explanation of the Cathode Ray Experiment provided on Vedantu. Vedantu has provided here a thorough explanation of the Cathode Ray Experiment along with Cathode Rays, How Do the Cathode Rays Work, Construction of a Cathode Ray Tube, Postulates of J.J. Thomson’s Atomic Model, and Practical Uses of Cathode Ray Tube Experiment along with examples. Students can learn the concepts of all the important topics of Science subject on Vedantu.

NCERT Study Material

J.J. Thomson

by: Ann Johnson

• 1.1 Biography
• 2 Electron Discovery
• 3 Cathode Ray Experiments
• 4 Isotopes and Mass Spectrometry
• 5.1 Further reading
• 5.2 External links
• 6 References

The Main Idea

J. J. Thomson was a Nobel Prize winning English physicist who used cathode rays to discover electrons. He also developed the mass spectrometer.

J. J. Thomson was born on December 18th, 1856 in England. His father wished he would become an engineer, however he could not find an apprenticeship. He attended Trinity College at Cambridge, and eventually headed the Cavendish Laboratory. Thomson married one of his students, Rose Paget, in 1892. They had two children, Joan and George Thomson. George eventually became a physicist and earned a Nobel Prize of his own. J. J. Thomson published over 200 papers and 13 books. He died on August 30th, 1940 in Cambridge and is buried in Westminster Abbey.

Electron Discovery

J. J. Thomson discovered the electron in 1897 while performing experiments on electric discharge in a high-vacuum cathode ray tube. He interpreted the deflection of the rays by electrically charged plates and magnets as "evidence of bodies much smaller than atoms." He later suggested that the atom is best represented as a sphere of positive matter, through which electrons are positioned by electrostatic forces.

Cathode Ray Experiments

A cathode ray tube is a glass tube with wiring inserted on both ends, and as much air as possible pumped out of it. Cathode rays were discovered to travel in straight lines, just like waves do. Physicists knew that the ray had an electric charge, and they were trying to figure out if that electric charge could be separated from the ray.

Thomson had the hypothesis that the ray and charge were inseparable, and designed experiments using a magnetic field to prove this was true. He first built a cathode ray tube with a metal cylinder at the end. The cylinder had slits in it that were attached to electrometers, that could measure electric charges. When he applied a magnetic field across the tube, no activity was recorded by the electrometers. This meant the charge had been bent away by the magnet. This proved his theory that the charge and the ray were inseparable.

Isotopes and Mass Spectrometry

After discovering the electron, Thomson started studying positive rays. Positive rays behaved very differently from cathode rays, and he found that each ray followed its own parabolic path based on its detection on the photographic plate. He reasoned that no two particles would follow the same path unless they possessed the same mass-to-charge ratio. He correctly suggested that the positively charged particles were formed by the loss of an electron (isotopes). This created the field of mass spectrometry, which is still used very heavily today.

Properties of matter, including mass and charge, are related to Thomson's work with electrons and the mass spectrometer.

Further reading

Thomson, J. J. (June 1906). "On the Number of Corpuscles in an Atom". Philosophical Magazine 11: 769–781. doi:10.1080/14786440609463496. Archived from the original on 19 December 2007. Retrieved 4 October 2008. Leadership and creativity : a history of the Cavendish Laboratory, 1871 - 1919

External links

http://www.cambridgenetwork.co.uk/news/cambridge-physicist-is-streets-ahead/

http://thomson.iqm.unicamp.br/thomson.phphttp://www.chemheritage.org/discover/online-resources/chemistry-in-history/themes/atomic-and-nuclear-structure/thomson.aspx http://www.biography.com/people/jj-thomson-40039 http://study.com/academy/lesson/jj-thomsons-cathode-ray-tube-crt-definition-experiment-diagram.htmlhttps://explorable.com/cathode-ray-experiment

[[Category:Notable Scientists]

Navigation menu

Famous Experiments: Cathode Rays that dealt  with the glowing paths revealed when currents of electricity provided by high voltage sources passed through evacuated glass tubes. He was to eventually declare that these mysterious "cathode rays" were actually beams of electrons, small building blocks of matter. is on the left. It is where the electrons originate. The anode, or positive terminal, is on the right and is the electrode towards which the electrons are being accelerated by the electric potential placed across the tube. A metal plate coated by phosphors is positioned inside the tube to detect the path of the electrons. It emits a green glow when struck by electrons. , his work with the discharge of electricity in gases earned him the . AVI film clip (1.2 Meg) pictures courtesy of   Copyright © 1997-2024 All rights reserved. Application Programmer     Mark Acton Table of Contents Random Entry Chronological Editorial Information About the SEP Editorial Board How to Cite the SEP Special Characters Advanced Tools Support the SEP PDFs for SEP Friends Make a Donation SEPIA for Libraries Back to Entry Entry Contents Entry Bibliography Academic Tools Friends PDF Preview Author and Citation Info Back to Top Supplement to Experiment in Physics Appendix 7: evidence for a new entity: j.j. thomson and the electron. In discussing the existence of electrons Ian Hacking has written, “So far as I’m concerned, if you can spray them then they are real” (Hacking 1983, p. 23). He went on to elaborate this view. “We are completely convinced of the reality of electrons when we set out to build—and often enough succeed in building—new kinds of device that use various well-understood causal properties of electrons to interfere in other more hypothetical parts of nature” (p. 265). Hacking worried that the simple manipulation of the first quotation, the changing of the charge on an oil drop or on a superconducting niobium sphere, which involves only the charge of the electron, was insufficient grounds for belief in electrons. His second illustration, which he believed more convincing because it involved several properties of the electron, was that of Peggy II, a source of polarized electrons built at the Stanford Linear Accelerator Center in the late 1970s. Peggy II provided polarized electrons for an experiment that scattered electrons off deuterium to investigate the weak neutral current. Although I agree with Hacking that manipulability can often provide us with grounds for belief in a theoretical entity, [ 1 ] his illustration comes far too late. Physicists were manipulating the electron in Hacking’s sense in the early twentieth century. [ 2 ] They believed in the existence of electrons well before Peggy II, and I will argue that they had good reasons for that belief. The position I adopt is one that might reasonably be called “conjectural” realism. It is conjectural because, despite having good reasons for belief in the existence of an entity or in the truth of a scientific law, we might be wrong. At one time scientists had good reason to believe in phlogiston and caloric, substances we now have good reason to believe don’t exist. My position includes both Sellars’ view that “to have good reason for holding a theory is ipso facto to have good reason for holding that the entities postulated by the theory exist” (Sellars 1962, p. 97), and the “entity realism” proposed by Cartwright (1983) and by Hacking (1983). Both Hacking, as noted above, and Cartwright emphasize the manipulability of an entity as a criterion for belief in its existence. Cartwright also stresses causal reasoning as part of her belief in entities. In her discussion of the operation of a cloud chamber she states, “…if there are no electrons in the cloud chamber, I do not know why the tracks are there” (Cartwright, 1983, p.99). In other words, if such entities don’t exist then we have no plausible causal story to tell. Both Hacking and Cartwright grant existence to entities such as electrons, but do not grant “real” status to either laws or theories, which may postulate or apply to such entities. In contrast to both Cartwright and Hacking, I suggest that we can also have good reasons for belief in the laws and theories governing the behavior of the entities, and that several of their illustrations implicitly involve such laws. [ 3 ] I have argued elsewhere for belief in the reality of scientific laws (Franklin 1996). In this section I shall concentrate on the reality and existence of entities, in particular, the electron. I agree with both Hacking and Cartwright that we can go beyond Sellars and have good reasons for belief in entities even without laws. Hacking and Cartwright emphasize experimenting with entities. I will argue that experimenting on entities and measuring their properties can also provide grounds for belief in their existence. In this section I will discuss the grounds for belief in the existence of the electron by examining J.J. Thomson’s experiments on cathode rays. His 1897 experiment on cathode rays is generally regarded as the “discovery” of the electron. The purpose of J.J. Thomson’s experiments was clearly stated in the introduction to his 1897 paper. The experiments discussed in this paper were undertaken in the hope of gaining some information as to the nature of Cathode Rays. The most diverse opinions are held as to these rays; according to the almost unanimous opinion of German physicists they are due to some process in the aether to which—inasmuch as in a uniform magnetic field their course is circular and not rectilinear—no phenomenon hitherto observed is analogous: another view of these rays is that, so far from being wholly aetherial, they are in fact wholly material, and that they mark the paths of particles of matter charged with negative electricity (Thomson 1897, p. 293). Thomson’s first order of business was to show that the cathode rays carried negative charge. This had presumably been shown previously by Perrin. Perrin placed two coaxial metal cylinders, insulated from one another, in front of a plane cathode. The cylinders each had a small hole through which the cathode rays could pass onto the inner cylinder. The outer cylinder was grounded. When cathode rays passed into the inner cylinder an electroscope attached to it showed the presence of a negative electrical charge. When the cathode rays were magnetically deflected so that they did not pass through the holes, no charge was detected. “Now the supporters of the aetherial theory do not deny that electrified particles are shot off from the cathode; they deny, however, that these charged particles have any more to do with the cathode rays than a rifle-ball has with the flash when a rifle is fired” (Thomson 1897, p. 294). Thomson repeated the experiment, but in a form that was not open to that objection. The apparatus is shown in Figure 14. The two coaxial cylinders with holes are shown. The outer cylinder was grounded and the inner one attached to an electrometer to detect any charge. The cathode rays from A pass into the bulb, but would not enter the holes in the cylinders unless deflected by a magnetic field. Figure 14. Thomson’s apparatus for demonstrating that cathode rays have negative charge. The slits in the cylinders are shown. From Thomson (1897). When the cathode rays (whose path was traced by the phosphorescence on the glass) did not fall on the slit, the electrical charge sent to the electrometer when the induction coil producing the rays was set in action was small and irregular; when, however, the rays were bent by a magnet so as to fall on the slit there was a large charge of negative electricity sent to the electrometer…. If the rays were so much bent by the magnet that they overshot the slits in the cylinder, the charge passing into the cylinder fell again to a very small fraction of its value when the aim was true. Thus this experiment shows that however we twist and deflect the cathode rays by magnetic forces, the negative electrification follows the same path as the rays, and that this negative electrification is indissolubly connected with the cathode rays (Thomson 1897, p. 294–295, emphasis added). This experiment also demonstrated that cathode rays were deflected by a magnetic field in exactly the way one would expect if they were negatively charged material particles. [ 4 ] Figure 15. Thomson’s apparatus for demonstrating that cathode rays are deflected by an electric field. It was also used to measure \(\bfrac{m}{e}\). From Thomson (1897). There was, however, a problem for the view that cathode rays were negatively charged particles. Several experiments, in particular those of Hertz, had failed to observe the deflection of cathode rays by an electrostatic field. Thomson proceeded to answer this objection. His apparatus is shown in Figure 15. Cathode rays from C pass through a slit in the anode A, and through another slit at B. They then passed between plates D and E and produced a narrow well-defined phosphorescent patch at the end of the tube, which also had a scale attached to measure any deflection. When Hertz had performed the experiment he had found no deflection when a potential difference was applied across D and E. He concluded that the electrostatic properties of the cathode ray are either nil or very feeble. Thomson admitted that when he first performed the experiment he also saw no effect. “on repeating this experiment [that of Hertz] I at first got the same result [no deflection], but subsequent experiments showed that the absence of deflexion is due to the conductivity conferred on the rarefied gas by the cathode rays”. [ 5 ] On measuring this conductivity it was found that it diminished very rapidly as the exhaustion increased; it seemed that on trying Hertz’s experiment at very high exhaustion there might be a chance of detecting the deflexion of the cathode rays by an electrostatic force (Thomson 1897, p. 296). Thomson did perform the experiment at lower pressure [higher exhaustion] and observed the deflection. [ 6 ] Thomson concluded: As the cathode rays carry a charge of negative electricity, are deflected by an electrostatic force as if they were negatively electrified, and are acted on by a magnetic force in just the way in which this force would act on a negatively electrified body moving along the path of these rays, I can see no escape from the conclusion that they are charges of negative electricity carried by particles of matter. (Thomson 1897, p. 302) [ 7 ] Having established that cathode rays were negatively charged material particles, Thomson went on to discuss what the particles were. “What are these particles? are they atoms, or molecules, or matter in a still finer state of subdivision” (p. 302). To investigate this question Thomson made measurements on the charge to mass ratio of cathode rays. Thomson’s method used both the electrostatic and magnetic deflection of the cathode rays. [ 8 ] The apparatus is shown in Figure 15. It also included a magnetic field that could be created perpendicular to both the electric field and the trajectory of the cathode rays. Let us consider a beam of particles of mass \(m\) charge \(e\), and velocity \(v\). Suppose the beam passes through an electric field F in the region between plates D and E, which has a length \(L\). The time for a particle to pass through this region \(t = \bfrac{L}{v}\). The electric force on the particle is \(Fe\) and its acceleration \(a = \bfrac{Fe}{m}\). The deflection d at the end of the region is given by Now consider a situation in which the beam of cathode rays simultaneously pass through both \(F\) and a magnetic field \(B\) in the same region. Thomson adjusted \(B\) so that the beam was undeflected. thus the magnetic force was equal to the electrostatic force. This determined the velocity of the beam. Thus, Each of the quantities in the above expression was measured so the \(\bfrac{e}{m}\) or \(\bfrac{m}{e}\) could be determined. Using this method Thomson found a value of \(\bfrac{m}{e}\) of \((1.29\pm 0.17) \times 10^{-7}\). This value was independent of both the gas in the tube and of the metal used in the cathode, suggesting that the particles were constituents of the atoms of all substances. It was also far smaller, by a factor of 1000, than the smallest value previously obtained, \(10^{-4}\), that of the hydrogen ion in electrolysis. Thomson remarked that this might be due to the smallness of \(m\) or to the largeness of \(e\). He argued that \(m\) was small citing Lenard’s work on the range of cathode rays in air. The range, which is related to the mean free path for collisions, and which depends on the size of the object, was 0.5 cm. The mean free path for molecules in air was approximately \(10^{-5}\) cm. If the cathode ray traveled so much farther than a molecule before colliding with an air molecule, Thomson argued that it must be much smaller than a molecule. [ 9 ] Thomson had shown that cathode rays behave as one would expect negatively charged material particles to behave. They deposited negative charge on an electrometer, and were deflected by both electric and magnetic fields in the appropriate direction for a negative charge. In addition the value for the mass to charge ratio was far smaller than the smallest value previously obtained, that of the hydrogen ion. If the charge were the same as that on the hydrogen ion, the mass would be far less. In addition, the cathode rays traveled farther in air than did molecules, also implying that they were smaller than an atom or molecule. Thomson concluded that these negatively charged particles were constituents of atoms. In other words, Thomson’s experiments had given us good reasons to believe in the existence of electrons. Return to Experiment in Physics Copyright © 2023 by Allan Franklin < allan . franklin @ colorado . edu > Slobodan Perovic < sperovic @ f . bg . ac . rs > Accessibility Support SEP Mirror sites. View this site from another server: Info about mirror sites The Stanford Encyclopedia of Philosophy is copyright © 2023 by The Metaphysics Research Lab , Department of Philosophy, Stanford University Library of Congress Catalog Data: ISSN 1095-5054 . suggested that they do. He advanced the idea that cathode rays are really streams of very small pieces of atoms. Three experiments led him to this.: of an 1895 experiment by Jean Perrin, Thomson built a ending in a pair of metal cylinders with a slit in them. These cylinders were in turn connected to an electrometer, a device for catching and measuring electrical charge. Perrin had found that cathode rays deposited an electric charge. Thomson wanted to see if, by bending the rays with a magnet, he could separate the charge from the rays. He found that when the rays entered the slit in the cylinders, the electrometer measured a large amount of negative charge. The electrometer did not register much electric charge if the rays were bent so they would not enter the slit. As Thomson saw it, the negative charge and the cathode rays must somehow be stuck together: you cannot separate the charge from the rays. . when physicists tried to bend cathode rays with an electric field. Now Thomson thought of a new approach. A charged particle will normally curve as it moves through an electric field, but not if it is surrounded by a conductor (a sheath of copper, for example). Thomson suspected that the traces of gas remaining in the tube were being turned into an electrical conductor by the cathode rays themselves. To test this idea, he took great pains to extract nearly all of the gas from a tube, and found that now the cathode rays did bend in an electric field after all. from these two experiments, "I can see no escape from the conclusion that [cathode rays] are charges of negative electricity carried by particles of matter." But, he continued, "What are these particles? are they atoms, or molecules, or matter in a still finer state of subdivision?" . sought to determine the basic properties of the particles. Although he couldn't measure directly the mass or the electric charge of such a particle, he could measure how much the rays were bent by a magnetic field, and how much energy they carried. From this data he could calculate the of the mass of a particle to its electric charge ( / ). He collected data using a variety of tubes and using different gases. . Just as Emil Wiechert had reported earlier that year, the mass-to-charge ratio for cathode rays turned out to be far smaller than that of a charged hydrogen atom--more than one thousand times smaller. Either the cathode rays carried an enormous charge (as compared with a charged atom), or else they were amazingly light relative to their charge. was settled by . Experimenting on how cathode rays penetrate gases, he showed that if cathode rays were particles they had to have a mass very much smaller than the mass of any atom. The proof was far from conclusive. But experiments by others in the next two years yielded an independent measurement of the value of the charge ( ) and confirmed this remarkable conclusion. the hypothesis that "we have in the cathode rays matter in a new state, a state in which the subdivision of matter is carried very much further than in the ordinary gaseous state: a state in which all matter... is of one and the same kind; this matter being the substance from which all the chemical elements are built up." 1897 Experiments Significance of Thomson's Experiment ( AQA A Level Physics ) Revision note. Comparing Specific Charge Thomson demonstrated the deflected particles in magnetic and electric fields must be negatively charged Previously, scientists had calculated the specific charge of a hydrogen ion (which as we now know, is a proton) Thomson's specific charge for an electron was around 1800 times larger than that of the hydrogen ion, as shown in the table below Specific charges of the electron and the hydrogen ion   ) Thomson's Experiment Recall that specific charge is defined as: The electron had a much smaller mass The electron had a much larger magnitude of charge Further experiments had to be performed to calculate the charge of an electron You've read 0 of your 10 free revision notes Unlock more, it's free, join the 100,000 + students that ❤️ save my exams. the (exam) results speak for themselves: Did this page help you? Use of SI Units & Their Prefixes Limitation of Physical Measurements Atomic Structure & Decay Equations Classification of Particles Conservation Laws & Particle Interactions The Photoelectric Effect Energy Levels & Photon Emission Longitudinal & Transverse Waves Stationary Waves Interference Author: Dan MG Expertise: Physics Dan graduated with a First-class Masters degree in Physics at Durham University, specialising in cell membrane biophysics. After being awarded an Institute of Physics Teacher Training Scholarship, Dan taught physics in secondary schools in the North of England before moving to SME. Here, he carries on his passion for writing enjoyable physics questions and helping young people to love physics. JJ Thompson’s Discovery of Electron: Cathode Ray Tube Experiment Explained JJ Thomson discovered the electron in 1897 and there are tons of videos about it.  However, most videos miss what JJ Thomson himself said was the motivating factor: a debate about how cathode rays move.  Want to know not only how but why electrons were discovered? Table of Contents The start of jj thomson, how thomson discovered electrons: trials and errors, thomson’s conclusion. A short history of Thomson: Joseph John Thomson, JJ on papers, to friends, and even to his own son [1] , was born in Lancashire, England to a middle class bookseller.  When he was 14 years old, Thomson planned to get an apprenticeship to a locomotive engineer but it had a long waiting list, so, he applied to and was accepted at that very young age to Owen’s college.  Thompson later recalled that, “the authorities at Owens College thought my admission was such a scandal – I expect they feared that students would soon be coming in perambulators  – that they passed regulations raising the minimum age for admission, so that such a catastrophe should not happen again. [2] ”  While in school, his father died, and his family didn’t have enough money for the apprenticeship.  Instead, he relied on scholarships at universities – ironically leading him to much greater fame in academia. In 1884, at the tender age of 28, Thomson applied to be the head of the Cavendish Research Institute.  He mostly applied as a lark and was as surprised as anyone to actually get the position!  “I felt like a fisherman who…had casually cast a line in an unlikely spot and hooked a fish much too heavy for him to land. [3] ”  Suddenly, he had incredible resources, stability and ability to research whatever he wished.  He ended up having an unerring ability to pinpoint interesting phenomena for himself and for others. In fact, a full eight of his research assistants and his son eventually earned Nobel Prizes, but, of course, like Thomson’s own Nobel Prize, that was in the future. Why did J. J. Thomson discover the electron in 1897?  Well, according to Thomson: “the discovery of the electron began with an attempt to explain the discrepancy between the behavior of cathode rays under magnetic and electric forces [4] .”  What did he mean by that?  Well, a cathode ray, or a ray in a vacuum tube that emanates from the negative electrode, can be easily moved with a magnet.  This gave a charismatic English chemist named William Crookes the crazy idea that the cathode ray was made of charged particles in 1879!  However, 5 years later, a young German scientist named Heinrich Hertz found that he could not get the beam to move with parallel plates, or with an electric field.  Hertz decided that Crookes was wrong, if the cathode ray was made of charged particles then it should be attracted to a positive plate and repulsed from a negative plate.  Ergo, it couldn’t be particles, and Hertz decided it was probably some new kind of electromagnetic wave, like a new kind of ultraviolet light.  Further, in 1892, Hertz accidentally discovered that cathode rays could tunnel through thin pieces of metal, which seemed like further proof that Crookes was so very wrong. Then, in December of 1895, a French physicist named Jean Perrin used a magnet to direct a cathode ray into and out of an electroscope (called a Faraday cylinder) and measured its charge.  Perrin wrote, “the Faraday cylinder became negatively charged when the cathode rays entered it, and only when they entered it; the cathode rays are thus charged with negative electricity . [5] ”  This is why JJ Thomson was so confused, he felt that Perrin had, “conclusive evidence that the rays carried a charge of negative electricity” except that, “Hertz found that when they were exposed to an electric force they were not deflected at all.”  What was going on? In 1896, Thomson wondered if there might have been something wrong with Hertz’s experiment with the two plates.  Thomson knew that the cathode ray tubes that they had only work if there is a little air in the tube and the amount of air needed depended on the shape of the terminals. Thomson wondered if the air affected the results.  Through trial and error, Thomson found he could get a “stronger” beam by shooting it through a positive anode with a hole in it.  With this system he could evacuate the tube to a much higher degree and, if the vacuum was good enough, the cathode ray was moved by electrically charged plates, “just as negatively electrified particles would be. [6] ” (If you are wondering why the air affected it, the air became ionized in the high electric field and became conductive.  The conductive air then acted like a Faraday cage shielding the beam from the electric field.) As stated before, Heinrich Hertz also found that cathode rays could travel through thin solids.  How could a particle do that?  Thomson thought that maybe particles could go through a solid if they were moving really, really fast.  But how to determine how fast a ray was moving?  Thomson made an electromagnetic gauntlet.  First, Thomson put a magnet near the ray to deflect the ray one-way and plates with electric charge to deflect the ray the other way.  He then added or reduced the charge on the plates so that the forces were balanced and the ray went in a straight line.  He knew that the force from the magnet depended on the charge of the particle, its speed and the magnetic field (given the letter B).  He also knew that the electric force from the plates only depended on the charge of the particle and the Electric field.  Since these forces were balanced, Thomson could determine the speed of the particles from the ratio of the two fields.  Thomson found speeds as big as 60,000 miles per second or almost one third of the speed of light.  Thomson recalled, “In all cases when the cathode rays are produced their velocity is much greater than the velocity of any other moving body with which we are acquainted. [7] ”   Thomson then did something even more ingenious; he removed the magnetic field.  Now, he had a beam of particles moving at a known speed with a single force on them.  They would fall, as Thomson said, “like a bullet projected horizontally with a velocity v and falling under gravity [8] ”.   Note that these “bullets” are falling because of the force between their charge and the charges on the electric plates as gravity is too small on such light objects to be influential.  By measuring the distance the bullets went he could determine the time they were in the tube and by the distance they “fell” Thomson could determine their acceleration.  Using F=ma Thomson determine the ratio of the charge on the particle to the mass (or e/m).  He found some very interesting results.  First, no matter what variables he changed in the experiment, the value of e/m was constant.  “We may… use any kind of substance we please for the electrodes and fill the tube with gas of any kind and yet the value of e/m will remain the same. [9] ”  This was a revolutionary result.  Thomson concluded that everything contained these tiny little things that he called corpuscles (and we call electrons).  He also deduced that the “corpuscles” in one item are exactly the same as the “corpuscles” in another.  So, for example, an oxygen molecule contains the same kind of electrons as a piece of gold!  Atoms are the building blocks of matter but inside the atoms (called subatomic) are these tiny electrons that are the same for everything . The other result he found was that the value of e/m was gigantic, 1,700 times bigger than the value for a charged Hydrogen atom, the object with the largest value of e/m before this experiment.   So, either the “corpuscle” had a ridiculously large charge or it was, well, ridiculously small.    A student of Thomson’s named C. T. R. Wilson had experimented with slowly falling water droplets that found that the charge on the corpuscles were, to the accuracy of the experiment, the same as the charge on a charged Hydrogen atom!   Thomson concluded that his corpuscles were just very, very, tiny, about 1,700 times smaller then the Hydrogen atom [1] .  These experiments lead Thomson to come to some interesting conclusions: Electrons are in everything and are well over a thousand times smaller then even the smallest atom.  Benjamin Franklin thought positive objects had too much “electrical fire” and negative had too little.  Really, positive objects have too few electrons and negative have too many.  Oops. Although since Franklin, people thought current flowed from the positive side to the negative, really, the electrons are flowing the other way.  When a person talks about “current” that flows from positive to negative they are talking about something that is not real!   True “electric current” flows from negative to positive and is the real way the electrons move. [although by the time that people believed J.J. Thomson, it was too late to change our electronics, so people just decided to stick with “current” going the wrong way!] Since electrons are tiny and in everything but most things have a neutral charge, and because solid objects are solid, the electrons must be swimming in a sea or soup of positive charges.  Like raisons in a raison cookie. The first three are still considered correct over one hundred years later.  The forth theory, the “plum pudding model” named after a truly English “desert” with raisins in sweet bread that the English torture people with during Christmas, was proposed by Thomson in 1904.  In 1908, a former student of Thomson’snamed Ernest Rutherford was experimenting with radiation, and inadvertently demolished the “plum pudding model” in the process.  However, before I can get into Rutherford’s gold foil experiment, I first want to talk about what was going on in France concurrent to Thomson’s experiments.  This is a story of how a new mother working mostly in a converted shed discovered and named the radium that Rutherford was experimenting with.  That woman’s name was Marie Sklodowska Curie, and that story is next time on the Lightning Tamers. [1] the current number is 1,836 but Thomson got pretty close [1] p 14 “Flash of the Cathode Rays: A History of JJ Thomson’s Electron” Dahl [2] Thompson, J.J. Recollections and Reflections p. 2 Referred to in Davis & Falconer JJ. Thompson and the Discovery of the Electron 2002 p. 3 [3] Thomson, Joseph John Recollections and Reflections p. 98 quoted in Davis, E.A & Falconer, Isabel JJ Thomson and the Discovery of the Electron 2002 p. 35 [4]   Thomson, JJ Recollections and Reflections p. 332-3 [5] “New Experiments on the Kathode Rays” Jean Perrin, December 30, 1985 translation appeared in Nature, Volume 53, p 298-9, January 30, 1896 [6] Nobel Prize speech? Related Posts How the inquisition led to the vacuum pump. How in the world would the inquisition lead to the invention of the vacuum pump? … The True Father of Electricity: Stephen Gray On May 1, 1729 a retired clothing dyer noticed a single feather moving in a… How Static Electricity Works How did gold lead to the first rules of electricity? And, why is it ½… Georg Matthias Bose: Crazy Experiments of the Enlightenment Am I really going to light a fire with my bare finger?  Of course, I… Leave a Comment Cancel Reply Your email address will not be published. Required fields are marked * Save my name, email, and website in this browser for the next time I comment. Discovery of the Electron: Cathode Rays First Online: 05 August 2020 Cite this chapter Bruce D. Popp 2   394 Accesses Poincaré’s work on dynamics of the electron provides a classical theory of subatomic charged particles to accompany the experimental work done over the decade following Jean Perrin’s work in 1895 . This chapter is the first of two parts that look at the discovery of the electron, the experimental work that established that electrical charge is discrete and that electrons have a mass that is small compared to hydrogen. J. J. Thomson measured the charge-to-mass ratio of cathode rays, establishing that they were particles (not radiation) and providing a distinctive property with which to identify the same particle in other contexts, including ionized gases and the photoelectric effect. This is an interpretation of what we mean when we say that he discovered the electron. This is a preview of subscription content, log in via an institution to check access. Access this chapter Subscribe and save. Get 10 units per month Download Article/Chapter or eBook 1 Unit = 1 Article or 1 Chapter Cancel anytime Available as PDF Read on any device Instant download Own it forever Available as EPUB and PDF Compact, lightweight edition Dispatched in 3 to 5 business days Free shipping worldwide - see info Durable hardcover edition Tax calculation will be finalised at checkout Purchases are for personal use only Institutional subscriptions Similar content being viewed by others The Interaction of Radiation with Matter Introduction to Part II Cherenkov Radiation Another aspect of Jean Perrin’s paper is worth noting. He wrote that he looked for positive charges corresponding to the negatively charged cathode rays and writes, “I think I found them in the same region where the cathode rays form.” (Perrin, 1895 ) These could be the channel rays (kanalstrahlen) discussed by Poincaré in (Poincaré, La dynamique de l’électron, 1908) section III and translated on page 107 of this book. https://data.bnf.fr/fr/12744499/henri_pellat/ When I, in an undergraduate physics laboratory many years ago, measured the mass-to-charge ratio of an electron, glasswork and vacuum pumps were not involved; I was shown an instrument on a laboratory table, told “do this,” “measure that,” and given a handout with more information. For information on who the Maxwellians were and what they did, see (Hunt, 1991 ). Notably, Oliver Heaviside, whose contribution to mathematical notation is discussed in Chap. 6 , is among them. To provide a relevant example, but without suggesting that it is more or less deserving of critique, consider the first chapter provided by A. B. Pippard from the University of Cambridge for the book Electron: a Centenary Volume (Springford, 1997 ). The adjective continental is used three times in the first 10 pages. An English adaptation of this paper was published within two months in The Electrician (Kaufmann , The Development of the Electron Idea, 1901b ). The adaptation does not include this list of references. A commercial gas mixture used for lighting. Falconer, I. (1987). Corpuscles, Electrons and Cathode Rays: J. J. Thomson and the ‘Discovery of the Electron’. British Journal for the History of Science , 241–276. Google Scholar   Halley, E. (1705). Synopsis of the Astronomy of Comets. London. Hunt, B. J. (1991). The Maxwellians. Ithaca, NY: Cornell University Press. Kaufmann, W. (1897). Die magnetische Ablenkbarkeit der Kathodenstrahlen und ihre Abhängigkeit vom Entladungspotential. Annalen der Physik, ser. 3, 61 , 544–552. Article   ADS   Google Scholar   Kaufmann, W. (1901a). Die Entwicklung des Electronenbegriffs. Physikalische Zeitschrift, 3 (1), 9–15. Kaufmann, W. (1901b, November 8). The Development of the Electron Idea. The Electrician, 48 , 95–97. Larmor, J. (1893). A Dynamical Theory of the Electric and Luminiferous Medium. Proceedings of the Royal Society of London, 54 , 438–461. National Institute of Standards and Technology. (n.d.-a). CODATA Value: electron charge to mass quotient . Retrieved November 12, 2019, from https://physics.nist.gov/cgi-bin/cuu/Value?esme National Institute of Standards and Technology. (n.d.-b). CODATA Value: proton-electron mass ratio . Retrieved July 6, 2019, from https://physics.nist.gov/cgi-bin/cuu/Value?mpsme Nobel Media AB 2019. (n.d.). The Nobel Prize in Physics 1906. Retrieved March 16, 2019, from NobelPrize.org : https://www.nobelprize.org/prizes/physics/1906/summary/ Perrin, J. (1895, December). Nouvelles propriétés des rayons cathodiques. Comptes Rendus des Séances de l’Académie des Sciences, 121 , 1130–34. Poincaré, H. (1906). Sur la dynamique de l’électron. Rendiconti del circolo matematico di Palermo, 21 , 129–176. Article   MATH   Google Scholar   Poincaré, H. (1908). La dynamique de l’électron. Revue générale des sciences pures et appliquées, 19 , 386–402. MATH   Google Scholar   Smith, G. E. (2001). J. J. Thomson and the Electron. 1897–99. In J. Z. Buchwald, & J. Warwick, Histories of the Electron: The Birth of Microphysics (pp. 21–76). Cambridge, MA: Dibner Institute for the History of Science and Technology. Springford, M. (Ed.). (1997). Electron: a Centenary Volume. Cambridge: Cambridge University Press. Stoney, G. J. (1891). On the Cause of Double Lines and of Equidistant Satellites in the Spectra of Gases. Scientific Transactions of the Royal Dublin Society, IV , 563–680. Stoney, G. J. (1894). Of the “Electron” or Atom of Electricity. Philosophical Magazine and Journal of Science, Fifth Series, 38 , 418–420. Article   Google Scholar   Thomson, J. J. (1897a, October). Cathode Rays. Philosophical Magazine and Journal of Science, Fifth Series, 44 , 293–316. Thomson, J. J. (1897b, May 21). Cathode Rays. The Electrician, 39 , 104–9. Thomson, J. J. (1897c, February). On the cathode rays. Proceedings of the Cambridge Philosophical Society, 9 , 243–4. Thomson, J. J. (1898). On the Charge of Electricity Carried by the Ions Produced by Röntgen Rays. Philosophical Magazine and Journal of Science, Fifth Series, 46 , 528–45. Thomson, J. J. (1899). On the Masses of Ions and Gases at Low Pressures. Philosophical Magazine, Fifth Series, 48 , 547–567. Wiechert, E. (1897a). Über das Wesen der Elektricität. Schriften der Physikalisch-Ökonomischen Gesellschaft zu Königsberg., 38 , 3–20. Wiechert, E. (1897b). Ueber das Wesen der Elektricität. Naturwissenschaftliche Rundschau, 12 , 237–239. Download references Author information Authors and affiliations. Norwood, MA, USA Bruce D. Popp You can also search for this author in PubMed   Google Scholar Rights and permissions Reprints and permissions Copyright information © 2020 Springer Nature Switzerland AG About this chapter Popp, B.D. (2020). Discovery of the Electron: Cathode Rays. In: Henri Poincaré: Electrons to Special Relativity. Springer, Cham. https://doi.org/10.1007/978-3-030-48039-4_7 Download citation DOI : https://doi.org/10.1007/978-3-030-48039-4_7 Published : 05 August 2020 Publisher Name : Springer, Cham Print ISBN : 978-3-030-48038-7 Online ISBN : 978-3-030-48039-4 eBook Packages : Physics and Astronomy Physics and Astronomy (R0) Share this chapter Anyone you share the following link with will be able to read this content: Sorry, a shareable link is not currently available for this article. Provided by the Springer Nature SharedIt content-sharing initiative Publish with us Policies and ethics Find a journal Track your research Stack Exchange Network Stack Exchange network consists of 183 Q&A communities including Stack Overflow , the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. Q&A for work Connect and share knowledge within a single location that is structured and easy to search. Cathode Rays Experiment by Sir J.J.Thomson From where do the electrons making cathode rays come? How is the gas in a discharge tube ionised? Do cosmic radiations affect it? 1 $\begingroup$ Where have you read about this experiment? Does it not tell you where the electrons come from? Have you tried searching the internet for a description of the experiment and how it works? $\endgroup$ –  sammy gerbil Commented Jul 9, 2016 at 20:23 Cathode Rays First, here's a diagram of a cathode ray tube: Cathode rays were named as such because they were emitted from the negative electrode, or cathode, of a high voltage generator. This was done in a vacuum tube. In the diagram, you can see the cathode, from which the rays (really electrons) were emitted. You can also see a tube that went to a vacuum pump. At the other end is the anode of the power supply. So, to answer your first question, To release electrons into the tube, they first must be detached from the atoms of the cathode. In the early cold cathode vacuum tubes, called Crookes tubes, this was done by using a high electrical potential between the anode and the cathode to ionize the residual gas in the tube; the ions were accelerated by the electric field and released electrons when they collided with the cathode.$^1$ So what little gas was left in the vacuum tube was ionized. The particles of gas were then accelerated by the electric field, hit the cathode, and knocked electrons off of the cathode. Discharge Tube Below is a diagram of a discharge tube: The ions were just naturally present in the air of the tube. The air around us has some ions in it, weakly ionized from cosmic rays or other sources. These ions were then accelerated from the anode to the cathode, creating a glow throughout the tube. Cosmic Rays Finally, I'm not sure what you mean by your last question. Cosmic rays weren't really a part of the experiment. Hope this helps! You can read more about cathode rays and discharge tubes here . $\begingroup$ Cathode ray tubes apparently can detect cosmic rays (radiation?) en.m.wikipedia.org/wiki/Electric_discharge_in_gases $\endgroup$ –  user108787 Commented Jul 9, 2016 at 20:38 $\begingroup$ @count_to_10: Why would one want to run a gas filled detector in discharge mode? That's usually highly uncalled for by the folks who are building them. Having said that, there are really cool examples of detectors that can visualize particles, I love this one (except for the noise): youtube.com/watch?v=DpW08xV3RI8 . As far as I know spark chambers are externally triggered, though. $\endgroup$ –  CuriousOne Commented Jul 9, 2016 at 20:43 $\begingroup$ @CuriousOne by coincidence I was reading Facts and Mysteries In Particle Physics" by T. Veltman yesterday, and the illustrations are a history lesson in detector technology. Did they record the sparks on film to analyse them later, or just get postgrads to sit in darkened rooms till their eyes burned out? $\endgroup$ –  user108787 Commented Jul 9, 2016 at 20:55 $\begingroup$ While I am "oldish", I am not quite old enough to have ever seen a spark chamber used for anything but as an exhibit piece. :-) I would have to do some research into old experiments to see where and how they were used. The discharge is restricted to a short amount of time (probably microseconds to milliseconds) and actively terminated. A precision analysis would certainly have required recording of some sort, but I don't know how they did it. @anna_v seems to have had direct exposure to pre-electronic detectors, while I missed that era by some time. $\endgroup$ –  CuriousOne Commented Jul 9, 2016 at 21:01 $\begingroup$ @count_to_10 - I'm not sure about cosmic ray seeking folks, but for Geiger, Marsden, Rutherford, et al., it was generally accepted that you could only count little flashes in the dark for about 10 minutes before your eyeballs went crazy. So, they traded off, ~5 minutes to adjust to the dark, 10 minutes to count, then out of the dark area... $\endgroup$ –  Jon Custer Commented Jul 9, 2016 at 23:11 Your Answer Sign up or log in, post as a guest. Required, but never shown By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy . Not the answer you're looking for? Browse other questions tagged electrons or ask your own question . Featured on Meta Upcoming initiatives on Stack Overflow and across the Stack Exchange network... Site maintenance - Wednesday, October 23, 2024, 9:00 PM-10:00 PM EDT... Our Help center policy article on generative AI content Hot Network Questions Why is toluene less acidic than cyclopentadiene? What is meant by ' total darkness' in Proverbs 20:20? If there is a reaction to the normal force, then why don’t we consider that in most cases? PhD program but no funding? Engineering reason as to why certain IS/PM brake adapters are front- and rear-specific? Why is Excel giving me a wrong solution to a system of equations? Problem with definition of tangent vectors as derivations Are cantrips prepared spells? Does using real-world month and day names invalidate the believability of a world that never had those cultures? Unwanted second label with european resistor in circuitikz Identify two unknown receptacles in 1950s US basement How to cut wooden beam into 4 parts that can be reassembled into a cube? There is mathematics in physics but is there any physics in mathematics? Strategy to roll a 10-sided die Which generation of hard drives no longer required you to park the heads? Why does the Gaza Strip use Israeli currency? How to tell if a charge is accelerating due to gravity or electric field? How to concatenate two GeoJSON vectors with different geometry type in QGIS Dance of The Knights puzzle Grimm's Law and PIE in general (How) can I use a color as an adverb? How do I make reimbursements easier on my students? What Exactly was The Baptist Saying? L'chatchila Ariber: what does it mean and where does it come from? Anatomy & Physiology Astrophysics Earth Science Environmental Science Organic Chemistry Precalculus Trigonometry English Grammar U.S. History World History ... and beyond Socratic Meta Featured Answers What are the conclusions of the Cathode ray experiment? Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript. View all journals Explore content About the journal Publish with us Sign up for alerts Published: 21 October 2024 Memristors with analogue switching and high on/off ratios using a van der Waals metallic cathode Yesheng Li   ORCID: orcid.org/0009-0006-9357-2412 1 , 2   na1 , Yao Xiong 3   na1 , Xiaolin Zhang 1 , Lei Yin   ORCID: orcid.org/0000-0002-4543-4510 1 , Yiling Yu 1 , Hao Wang 1 , Lei Liao   ORCID: orcid.org/0000-0003-1325-2410 4 & Jun He   ORCID: orcid.org/0000-0002-5998-5225 1 , 5 , 6   Nature Electronics ( 2024 ) Cite this article Metrics details Electrical and electronic engineering Electronic devices Information storage Two-dimensional materials Neuromorphic computing based on memristors could help meet the growing demand for data-intensive computing applications such as artificial intelligence. Analogue memristors with multiple conductance states are of particular use in high-efficiency neuromorphic computing, but their weight mapping capabilities are typically limited by small on/off ratios. Here we show that memristors with analogue resistive switching and large on/off ratios can be created using two-dimensional van der Waals metallic materials (graphene or platinum ditelluride) as the cathodes. The memristors use silver as the top anode and indium phosphorus sulfide as the switching medium. Previous approaches have focused on modulating ion motion using changes to the resistive switching layer or anode, which can lower the on/off ratios. In contrast, our approach relies on the van der Waals cathode, which allows silver ion intercalation/de-intercalation, creating a high diffusion barrier to modulate ion motion. The strategy can achieve analogue resistive switching with an on/off ratio up to 10 8 , over 8-bit conductance states and attojoule-level power consumption. We use the analogue properties to perform the chip-level simulation of a convolutional neural network that offers high recognition accuracy. This is a preview of subscription content, access via your institution Access options Access Nature and 54 other Nature Portfolio journals Get Nature+, our best-value online-access subscription 24,99 € / 30 days cancel any time Subscribe to this journal Receive 12 digital issues and online access to articles 111,21 € per year only 9,27 € per issue Buy this article Purchase on SpringerLink Instant access to full article PDF Prices may be subject to local taxes which are calculated during checkout Data availability The data that support the findings of this study are available from the corresponding authors upon reasonable request. Lanza, M. et al. Memristive technologies for data storage, computation, encryption, and radio-frequency communication. Science 376 , eabj9979 (2022). Article   Google Scholar   Kendall, J. D. & Kumar, S. The building blocks of a brain-inspired computer. Appl. Phys. Rev. 7 , 011305 (2020). Rao, M. et al. Thousands of conductance levels in memristors integrated on CMOS. Nature 615 , 823–829 (2023). Zhao, M., Gao, B., Tang, J., Qian, H. & Wu, H. Reliability of analogue resistive switching memory for neuromorphic computing. Appl. Phys. Rev. 7 , 011301 (2020). Zhang, W. et al. Neuro-inspired computing chips. Nat. Electron. 3 , 371–382 (2020). Tang, B. et al. Wafer-scale solution-processed 2D material analogue resistive memory array for memory-based computing. Nat. Commun. 13 , 3037 (2022). Rana, A. M., Ismail, M., Akber, T., Nadeem, M. Y. & Kim, S. Transition from unipolar to bipolar, multilevel switching, abrupt and gradual reset phenomena in a TaN/CeO 2 /Ti/Pt memory devices. Mater. Res. Bull. 117 , 41–47 (2019). Gawai, U., Kumar, D., Singh, A., Wu, C.-H. & Chang, K.-M. Oxygen vacancies controlled highly stable bilayer analogue synapse used for neuromorphic computing systems. ACS Appl. Electron. Mater. 4 , 4265–4272 (2022). Mohanty, S. K. et al. Uniform resistive switching and highly stable synaptic characteristics of HfO x sandwiched TaO x -based memristor for neuromorphic system. Ceram. Int. 49 , 16909–16917 (2023). Lu, X. F. et al. Exploring low power and ultrafast memristor on p-type van der Waals SnS. Nano Lett. 21 , 8800–8807 (2021). Yang, Y. et al. Electrochemical dynamics of nanoscale metallic inclusions in dielectrics. Nat. Commun. 5 , 4232 (2014). Wu, F. C. et al. Interface engineering via MoS 2 insertion layer for improving resistive switching of conductive-bridging random access memory. Adv. Electron. Mater. 5 , 1800747 (2019). Ismail, M., Abbas, H., Choi, C. & Kim, S. Controllable analogue resistive switching and synaptic characteristics in ZrO 2 /ZTO bilayer memristive device for neuromorphic systems. Appl. Surf. Sci. 529 , 147107 (2020). Li, S. et al. Wafer-scale 2D hafnium diselenide based memristor crossbar array for energy-efficient neural network hardware. Adv. Mater. 34 , 2103376 (2021). Li, Y. et al. In-memory computing using memristor arrays with ultrathin 2D PdSeO x /PdSe 2 heterostructure. Adv. Mater. 34 , 2201488 (2022). Xu, J. et al. Tunable digital-to-analogue switching in Nb 2 O 5 -based resistance switching devices by oxygen vacancy engineering. Appl. Surf. Sci. 579 , 152114 (2022). Saleem, A. et al. Transformation of digital to analogue switching in TaO x -based memristor device for neuromorphic applications. Appl. Phys. Lett. 118 , 112103 (2021). Hu, L. X. et al. Ultrasensitive memristive synapses based on lightly oxidized sulfide films. Adv. Mater. 29 , 1606927 (2017). Belmonte, A. et al. Voltage-controlled reverse filament growth boosts resistive switching memory. Nano Res. 11 , 4017–4025 (2018). Jeon, H. et al. Resistive switching behaviors of Cu/TaO x /TiN device with combined oxygen vacancy/copper conductive filaments. Curr. Appl. Phys. 15 , 1005–1009 (2015). Chen, S. et al. Wafer-scale integration of two-dimensional materials in high-density memristive crossbar arrays for artificial neural networks. Nat. Electron. 3 , 638–645 (2020). Kadhim, M. S. et al. Existence of resistive switching memory and negative differential resistance state in self-colored MoS 2 /ZnO heterojunction devices. ACS Appl. Electron. Mater. 1 , 318–324 (2019). Ahn, W. et al. A highly reliable molybdenum disulfide-based synaptic memristor using a copper migration-controlled structure. Small 19 , 2300223 (2023). Xie, J., Afshari, S. & Sanchez Esqueda, I. Hexagonal boron nitride (h-BN) memristor arrays for analogue-based machine learning hardware. npj 2D Mater. Appl. 6 , 50 (2022). Pan, C. B. et al. Coexistence of grain-boundaries-assisted bipolar and threshold resistive switching in multilayer hexagonal boron nitride. Adv. Funct. Mater. 27 , 1604811 (2017). Yeon, H. et al. Alloying conducting channels for reliable neuromorphic computing. Nat. Nanotechnol. 15 , 574–579 (2020). Google Scholar   Weng, Z. et al. High-performance memristors based on few-layer manganese phosphorus trisulfide for neuromorphic computing. Adv. Funct. Mater. 34 , 2305386 (2023). Weng, Z. et al. Reliable memristor crossbar array based on 2D layered nickel phosphorus trisulfide for energy-efficient neuromorphic hardware. Small 20 , 2304518 (2023). Zhou, J. et al. Layered intercalation materials. Adv. Mater. 33 , 2004557 (2021). Gonzalez-Rosillo, J. C. et al. Lithium-battery anode gains additional functionality for neuromorphic computing through metal–insulator phase separation. Adv. Mater. 32 , 1907465 (2020). Zhu, X. J., Li, D., Liang, X. G. & Lu, W. D. Ionic modulation and ionic coupling effects in MoS 2 devices for neuromorphic computing. Nat. Mater. 18 , 141–148 (2019). Seo, S. et al. Artificial van der Waals hybrid synapse and its application to acoustic pattern recognition. Nat. Commun. 11 , 3936 (2020). Xu, Y. B. et al. In situ, atomic-resolution observation of lithiation and sodiation of WS 2 nanoflakes: implications for lithium-ion and sodium-ion batteries. Small 17 , e2100637 (2021). Peng, X., Huang, S., Jiang, H., Lu, A. & Yu, S. DNN+NeuroSim V2.0: an end-to-end benchmarking framework for compute-in-memory accelerators for on-chip training. IEEE Trans. Comput.-Aided Design Integr. Circuits Syst. 40 , 2306–2319 (2021). Peng, X. et al. DNN+NeuroSim: an end-to-end benchmarking framework for compute-in-memory accelerators with versatile device technologies. In 2019 IEEE International Electron Devices Meeting (IEDM) 32.5.1–32.5.4 (IEEE, 2019). Burr, G. W. et al. Neuromorphic computing using non-volatile memory. Adv. Phys. X 2 , 89–124 (2017). Kresse, G. & Hafner, J. Ab initio molecular-dynamics simulation of the liquid-metal–amorphous-semiconductor transition in germanium. Phys. Rev. B 49 , 14251–14269 (1994). Blöchl, P. E. Projector augmented-wave method. Phys. Rev. B 50 , 17953–17979 (1994). Hammer, B., Hansen, L. B. & Norskov, J. K. Improved adsorption energetics within density-functional theory using revised Perdew-Burke-Ernzerhof functionals. Phys. Rev. B 59 , 7413–7421 (1999). Henkelman, G. & Jonsson, H. Improved tangent estimate in the nudged elastic band method for finding minimum energy paths and saddle points. J. Chem. Phys. 113 , 9978–9985 (2000). Sheppard, D., Terrell, R. & Henkelman, G. Optimization methods for finding minimum energy paths. J. Chem. Phys. 128 , 134106 (2008). Download references Acknowledgements This work is supported by the National Key R&D Program of China (no. 2018YFA0703700 (J.H.)), National Natural Science Foundation of China (nos. U23A20364 (J.H.) and 62204175 (Y.L.)), Natural Science Foundation of Jiangsu Province (no. BK20220280 (Y.L.)) and Natural Science Foundation of Hubei Province (no. 2022CFB735 (Y.L.)). We also acknowledge the Center for Electron Microscopy of Wuhan University for their substantial support. Author information These authors contributed equally: Yesheng Li, Yao Xiong. Authors and Affiliations Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, and School of Physical and Technology, Wuhan University, Wuhan, China Yesheng Li, Xiaolin Zhang, Lei Yin, Yiling Yu, Hao Wang & Jun He Suzhou Institute of Wuhan University, Suzhou, China School of Science, Wuhan University of Technology, Wuhan, China State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Semiconductors (College of Integrated Circuits), Hunan University, Changsha, China Wuhan Institute of Quantum Technology, Wuhan, China Institute of Semiconductors, Henan Academy of Sciences, Zhengzhou, China You can also search for this author in PubMed   Google Scholar Contributions This project was supervised and directed by J.H. and Y.L. Y.L. conceived this work. Y.L. and Y.X. designed the experiments. Y.L. and L.Y. conducted the device fabrication and electrical measurements. Y.L., H.W., Y.Y. and L.L. performed the material characterization. X.Z. conducted the density functional theory calculation. Y.X. performed the image recognition. All authors contributed to the discussion and analysis of the results. Y.L. wrote the manuscript. Corresponding authors Correspondence to Yesheng Li or Jun He . Ethics declarations Competing interests. The authors declare no competing interests. Peer review Peer review information. Nature Electronics thanks Wenjing Jie, Huajun Sun and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Additional information Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Supplementary information Supplementary information. Supplementary Figs. 1–39, Tables 1–4, Notes 1–5 and References. Rights and permissions Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law. Reprints and permissions About this article Cite this article. Li, Y., Xiong, Y., Zhang, X. et al. Memristors with analogue switching and high on/off ratios using a van der Waals metallic cathode. Nat Electron (2024). https://doi.org/10.1038/s41928-024-01269-y Download citation Received : 23 November 2023 Accepted : 27 September 2024 Published : 21 October 2024 DOI : https://doi.org/10.1038/s41928-024-01269-y Share this article Anyone you share the following link with will be able to read this content: Sorry, a shareable link is not currently available for this article. Provided by the Springer Nature SharedIt content-sharing initiative Quick links Explore articles by subject Guide to authors Editorial policies Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily. 144 IMAGES Cathode Ray Experiment by J.J. Thomson Goldstein cathode ray experiment Cathode Ray Tube Experiment Procedure & Diagram J.J. Thomson's Cathode Ray Tube (CRT): Definition, Experiment & Diagram Cathode ray experiment || Discharge tube experiment || Discovery of electron || Class 9th Cathode Ray Tube Experiments VIDEO Cathode Ray Tube #sachinsir #animation #physics #physicswallah Cathode ray tube experiment #chemistry #experiment #science cathode Ray Tube experiment👍#scientists#scientistswhoselfie #littlescientists#futurescientists Cathode Ray Experiment cathode ray experiment part 2 class 11 LHS Cathode Ray Tube Experiment 2021-2022 COMMENTS Cathode Ray Experiment by JJ.Thomson (CRT) Cathode Ray Tube - The Cathode Ray Experiment by J.J.Thomson helped to discover electrons. Cathode ray tube is the heart of the oscilloscope and it generates the electron bean, accelerates the beam and deflects the beam. Visit BYJUS to learn more about it. Cathode Ray Tube Experiment The cathode ray tube experiment performed by J.J. Thomson demonstrated the existence of the electron. Scientist had believed in the existence of a negative particle for some time. So much so, that George Stoney (1891) proposed the name electron for the particle. However, it wasn't till about 1898 that the electron was shown to exist by J.J ... JJ Thomson, electrons and the Cathode Ray Tube Cathode rays form when electrons emit from one electrode and travel to another. The transfer occurs due to the application of a voltage in vacuum. Thomson also determined the mass to charge ratio of the electron using a cathode ray tube, another significant discovery. Cathod ray tube, which was used by Thomson to discover the electron Cathode Ray Experiment by J. J. Thomson Thomson's First Cathode Ray Experiment. Thomson had an inkling that the 'rays' emitted from the electron gun were inseparable from the latent charge, and decided to try and prove this by using a magnetic field. His first experiment was to build a cathode ray tube with a metal cylinder on the end. This cylinder had two slits in it, leading ... J.J. Thomson's Cathode Ray Tube Experiment The cathode ray tube experiment conducted by J.J. Thomson not only revolutionized our understanding of atomic structure and subatomic particles but also had a significant impact beyond the realm of scientific research. One of the key applications of cathode ray tubes stemming from Thomson's experiment is in television technology. These ... Cathode Ray Experiment by J.J. Thomson Cathode Ray Experiment, also known as the Crookes tube experiment, is a historically significant experiment in the field of physics that helped scientists understand the nature of electrons.English scientist Sir J.J. Thomson performed an experiment using a Cathode Ray Tube, which led to the discovery of an electron.. In this article, we will discuss this significant experiment, including ... Cathode Ray Tube (CRT) Thomson's First CRT Experiment. Thomson took a cathode ray tube, and at the place where the electron beam was supposed to strike, he positioned a pair of metal cylinders having slits on them. The pair, in turn, was connected to an electrometer, a device for catching and measuring electric charges. Then, on operating the CRT, in the absence of ... Joseph John "J. J." Thomson The British physicist Joseph John "J. J." Thomson (1856-1940) performed a series of experiments in 1897 designed to study the nature of electric discharge in a high-vacuum cathode-ray tube, an area being investigated by many scientists at the time. J J Thomson Cathode Ray Tube Experiment - J.J. Thompson, conducted the cathode ray tube experiment to prove that rays emitted from an electron gun are inseparable from the latent charge. He built his cathode ray tube with a metal cylinder on the other end. J.J. Thomson Cathode Ray Experiments. A cathode ray tube is a glass tube with wiring inserted on both ends, and as much air as possible pumped out of it. Cathode rays were discovered to travel in straight lines, just like waves do. Physicists knew that the ray had an electric charge, and they were trying to figure out if that electric charge could be ... J.J. Thomson's Cathode Ray Tube Experiment Understand the cathode ray definition and how it works. Discover which scientist used the cathode ray tube. Learn about JJ Thomson's experiments on... PhysicsLAB: Famous Experiments: Cathode Rays In the 1970's-1990's, computer monitors were large and extremely heavy CRTs, or cathode ray tubes. They were also based on the previous technology of television picture tubes. LCD and plasma television screens emerged in the mass market around 2009. In recent years, these monitors and screens have become lighter, larger, and less expensive. Experiment in Physics > Appendix 7: Evidence for a New Entity: J.J In this section I will discuss the grounds for belief in the existence of the electron by examining J.J. Thomson's experiments on cathode rays. His 1897 experiment on cathode rays is generally regarded as the "discovery" of the electron. The purpose of J.J. Thomson's experiments was clearly stated in the introduction to his 1897 paper. Three Experiments and One Big Idea irst, in a variation of an 1895 experiment by Jean Perrin, Thomson built a cathode ray tube ending in a pair of metal cylinders with a slit in them. These cylinders were in turn connected to an electrometer, a device for catching and measuring electrical charge. Perrin had found that cathode rays deposited an electric charge. Significance of Thomson's Experiment Revision notes on 12.1.4 Significance of Thomson's Experiment for the AQA A Level Physics syllabus, written by the Physics experts at Save My Exams. Home. ... 9.2.12 Supernovae & Gamma Ray Bursts (GRBs) 9.2.13 Supernovae as Standard Candles; ... 12.1.1 Cathode Rays; 12.1.2 Thermionic Emission; 12.1.3 Specific Charge Experiments; JJ Thompson's Discovery of Electron: Cathode Ray Tube Experiment Explained In 1896, Thomson wondered if there might have been something wrong with Hertz's experiment with the two plates. Thomson knew that the cathode ray tubes that they had only work if there is a little air in the tube and the amount of air needed depended on the shape of the terminals. Thomson wondered if the air affected the results. Discovery of the Electron: Cathode Rays The introduction to the experiment described in the first section of (Thomson, Cathode Rays, 1897a), "Charge Carried by the Cathode Rays," reinforces this perspective. The description starts with a reference to an experiment done by Jean Perrin. J. J. PDF Chapter 7 Discovery of the Electron: Cathode Rays The introduction to the experiment described in the first section of (Thomson, Cathode Rays, 1897a), "Charge Carried by the Cathode Rays," reinforces this perspective. The description starts with a reference to an experiment done by Jean Perrin. J. J. Thomson does not provide a reference; however, it seems unambiguous Cathode Rays Experiment by Sir J.J.Thomson Cathode Rays. First, here's a diagram of a cathode ray tube: Cathode rays were named as such because they were emitted from the negative electrode, or cathode, of a high voltage generator. This was done in a vacuum tube. In the diagram, you can see the cathode, from which the rays (really electrons) were emitted. What are the conclusions of the Cathode ray experiment? His experiments were all conducted with what is known as a cathode ray tube, so firstly I will try to explain what this is and how it works. A cathode ray tube is a hollow sealed glass tube which is under vacuum (has had all the air sucked out of it). Inside at one end is an electrical filament (which is actually called the cathode in this experiment) just like the one inside a light bulb. At ... Memristors with analogue switching and high on/off ratios ... First, to verify the Ag permeation in the vdW-cathode, cross-sectional (CS) transmission electron microscopy (TEM) images as well as the energy-dispersive X-ray spectroscopy (EDS) mapping of the ... essay homework paper phd project resume review speech study thesis