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प्रश्न
What do you mean by electron emission?
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उत्तर
Free electrons leave the metal surface only if sufficient energy is supplied to the metal. This emission of electrons from metal surface is called the electron emission.
संबंधित प्रश्न
Answer the following questions based on a hot cathode ray tube.
What will happen to the beam when it passes through the electric field?
In a cathode ray tube state:
(i) the purpose of covering cathode by thorium and carbon.
(ii) the purpose of the fluorescent screen.
(iii) how is it possible to increase the rate of emission of electrons.
What kind of change takes place in a nucleus when a β -particle is emitted?
What is nucleus of an atom? Compare its size with that of the atom. Name its constitutents. How is the number of these constituents determined by the atomic number its atomic model.
In a cathode ray tube state the purpose of the fluorescent screen.
Name a common device where a hot cathode ray tube is used.
A certain nucleus has a mass number 20 and atomic number 9. Find the number of neutrons and protons present in it.
State one use of radio-isotopes.
88Ra226 experiences three α - decay. Find the number of neutrons in the daughter element.
