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प्रश्न
State two properties that a substance should possess when used as a thermionic emitter.
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उत्तर
Two properties are:
(i) High melting point. (ii) Low work function.
संबंधित प्रश्न
A radiation X is focused by a particular device on the bulb of a thermometer and mercury in the thermometer shows a rapid increase. Name the radiation X
Radiations given out from a source when subjected to an electric field in a direction perpendicular to their path are shown below in the diagram. The arrows show the path of the radiation A, B and C. Answer the following questions in terms of A, B and C.
1) Name the radiation B which is unaffected by the electrostatic field.
2) Why does the radiation C deflect more than A?
3) Which among the three causes the least biological damage externally.
4) Name the radiation which is used in carbon dating.
What do you understand by the term radioactivity?
Are all the radiations viz. α, β and γ emitted in a single radioactive decay?
A certain nucleus has a mass number 20 and atomic number 9. Find the number of neutrons and protons present in it.
From α, β and γ-rays, name the one which travels with the speed of light?
From α, β and γ-rays, name the one which is not affected by electric or magnetic field?
Heavy radioactive elements eventually turn into ______.
When an α-particle of mass m moving with velocity ν bombards on a heavy nucleus of charge Ze, its distance of closest approach from the nucleus depends on m as:
