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Why can cathode rays be observed and manipulated within a vacuum tube and not in air?
Wiki User
∙ 15y ago
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.
Wiki User
∙ 15y ago
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What did scientists conclude from observing that within a cathode tube cathode rays could move a paddle wheel placed in their paths?
bullcrap
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.
Can sound be heard in a vacuum?
No.Sound consists of mechanical vibrations within a medium (such as the air). Within a vacuum, there is no such medium, and thus no sound.(However, solid objects will still vibrate in a vacuum, and an observer in direct contact with a vibrating object would be able to "hear" these vibrations despite the lack of air.)
Sound waves can't travel through A a solid B a liquid C an elastic material D a vacuum?
Sound waves cannot travel through a vacuum because it needs a medium and a vacuum has nothing within it that can act as a medium.
What does the electron microscope measure?
Within the field of virology, virus particles can be manually counted, and the morphology of these particles can be observed (ie, if it has an evelope, etc).
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 can data be manipulated within your computer?
gxfjgngjmhg
What did scientists conclude from observing that within a cathode tube cathode rays could move a paddle wheel placed in their paths?
bullcrap
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.
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.
Within which object was a supernova observed in 1987?
large magellanic cloud.
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.
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.
How many vacuum tube in one transistor?
There are no vacuum tubes in a transistor. A vacuum tube is an electronic device that uses a heated cathode in a vacuum to direct and control an electron stream to an anode, also known as the plate. The vacuum tube is old technology, but it is still used today, typically in high power applications such as transmitters. A transistor is an electronic device that uses solid-state semiconductors to similarly control an electron stream. The transistor is newer than the vacuum tube. It offers lower power, smaller size, easier use and other enhancements over vacuum tubes, within limits, of course, such as voltage and power.
What is the opposite of vacuum?
== == The opposite of a vacuum is a volume of matter. the opposite of a vacuum is a volume completely filled with matter... a space with no empty spaces within it... the given name for which being Plenum...
Can sound be heard in a vacuum?
No.Sound consists of mechanical vibrations within a medium (such as the air). Within a vacuum, there is no such medium, and thus no sound.(However, solid objects will still vibrate in a vacuum, and an observer in direct contact with a vibrating object would be able to "hear" these vibrations despite the lack of air.)
What are two judaism hoildays?
1). Sabbath, observed every Saturday. 2). New Month, observed within the first few days after every new moon.
