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Why can cathode rays be observed and manipulated within a vacuum tube and not in air?
Actually, they cannot be observed even in a vacuum tube. In a CRT, or cathode ray tube, electrons (this is what "cathode rays" are) are emitted by a heated cathode that is at a negative potential, accelerated by being attracted to a very high positive voltage and magnetically steered so they impact a screen coated with phosphors. When the beam hits the phosphor coating, the phosphor emits visible light. This is what we see, not the electron beam itself. Electrons are free to travel in a vacuum, but they are quickly stopped in air by interacting with all the atoms of gas floating about. This is one reason the air is removed in a CRT, not to mention the hot cathode would almost instantly burn out if air (containing oxygen) were present.
What else can I help you with?
Where does the thermionic emission occur in cathode rays tube?
Thermionic emission occurs at the cathode in a cathode ray tube, which is a vacuum tube that generates electron beams. When the cathode is heated, electrons are emitted and accelerated towards the anode, leading to the generation of cathode rays within the tube.
What did JJ Thomson's cathode-ray tube experiment show?
Thompson observed that these rays are negatively electrically charged.
What did scientists conclude from observing that within a cathode tube cathode rays could move a paddle wheel placed in their paths?
Scientists concluded that cathode rays were negatively charged particles that carried momentum. They inferred this from the movement of the paddle wheel, which indicated that the cathode rays possessed kinetic energy and could transfer their momentum to the wheel as they collided with it.
What is the property common to all electromagnetic waves within a vacuum?
The property common to all electromagnetic waves within a vacuum is that they all travel at the speed of light.
What is the solution to a cathode ray tube physics problem involving electron acceleration and deflection?
The solution to a cathode ray tube physics problem involving electron acceleration and deflection is to apply the principles of electromagnetism and the laws of motion to calculate the trajectory of the electrons as they are accelerated and deflected by electric and magnetic fields within the tube. By solving the relevant equations, one can determine the path of the electrons and predict their behavior within the cathode ray tube.
Where does the thermionic emission occur in cathode rays tube?
Thermionic emission occurs at the cathode in a cathode ray tube, which is a vacuum tube that generates electron beams. When the cathode is heated, electrons are emitted and accelerated towards the anode, leading to the generation of cathode rays within the tube.
How does a vacuum tube work?
contains only a heated electron-emitting cathode and an anode. Electrons can only flow in one direction through the device—from the cathode to the anode. Adding one or more control grids within the tube allows the current between the cathode and anode to be controlled by the voltage on the grids.[5]
How did Thomson know that atoms must contain particles with positive charges?
He knew that in a vacuum tube metals can be made to emit streams of negative charge which were then called cathode rays. If atoms are neutral and can produce negative charge, there must be positive charge there too.
What did JJ Thomson's cathode-ray tube experiment show?
Thompson observed that these rays are negatively electrically charged.
How can data be manipulated within your computer?
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How were electrons produced from the cathode ray ube?
Electrons were produced in a cathode ray tube by applying a high voltage to the cathode, causing electrons to be emitted through thermionic emission. These electrons were then accelerated towards the anode by the electric field within the tube, creating a beam of electrons known as the cathode ray.
What did JJ Thompson's Cathode ray experiment suggest?
J.J. Thomson's cathode ray experiment suggested the existence of negatively charged particles, later known as electrons. By studying the behavior of cathode rays in a vacuum tube, Thomson determined that these particles were much smaller than atoms and had a negative charge. This discovery led to the development of the plum pudding model of the atom.
Why do you say cathode rays are electrons?
Because -- they are? Or, more specifically, because the particles within cathode rays act exactly like electrons. They either ARE electrons or they do a REAL good job of imitating them.
What did scientists conclude from observing that within a cathode tube cathode rays could move a paddle wheel placed in their paths?
Scientists concluded that cathode rays were negatively charged particles that carried momentum. They inferred this from the movement of the paddle wheel, which indicated that the cathode rays possessed kinetic energy and could transfer their momentum to the wheel as they collided with it.
What is the property common to all electromagnetic waves within a vacuum?
The property common to all electromagnetic waves within a vacuum is that they all travel at the speed of light.
Where are the cavities that give a cavity magnetron vacuum tube its name?
The cavities in a cavity magnetron are actual hollow spaces of a specific size and shape within the tube that set up conditions to generate oscillating microwave energy. They are arranged around the cathode inside the vacuum envelope. It may be helpful to look at pictures rather than read words, so segue to the web and look at images.--------------------------------The cavities are machined into the anode.
In a vacuum there is no matter. do you think conduction can take place in vacuum?
Conduction cannot occur within a vacuum because it requires a substrate (i.e. matter) for energy to be transferred.
