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प्रश्न
How can they be made to leave the metal surface? (State any two ways)
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उत्तर
Electron emission from the metal surface can be (any two):
1) Thermionic emission – when energy is supplied as heat
2) Photoelectric emission – when energy is supplied as energy.
3) Field emission – when energy is supplied by applying an electric field to accelerate the electrons.
4) Secondary emission – when energy is supplied from the kinetic energy of other electrons on collisions with them.
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संबंधित प्रश्न
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State the approximate voltage used to heat the filament
What do you mean by Mass number.
In the following fig. shows a radioactive source S in a thick lead container. The radiations pass through an electric field between the plates P and Q. Complete the diagram to show the paths of α , β and γ radiations.
Why is the source S placed in a thick lead container?
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During the emission of a beta particle, the ______ number remains same.
State two properties that a substance should possess when used as a thermionic emitter.
In a cathode ray tube state the purpose of covering cathode by thorium and carbon.
Are all the radiations viz. α, β and γ emitted in a single radioactive decay?
An electrons emitter must have how much work function and melting point.
State three ways of obtaining an electron-beam.
