Advertisements
Advertisements
Question
State two characteristics of the substance used as thermionic emitter.
Advertisements
Solution
(i) The substance must have high melting point.
(ii) The work function of the substance should be low so that electrons may be emitted even at low temperature.
APPEARS IN
RELATED QUESTIONS
An electromagnetic radiation is used for photography in fog. [2]
(i) Identify the radiation.
(ii) Why is this radiation mentioned by you, ideal for this purpose ?
A nucleus of an element X which has the symbol `""_84^202` X emits an alpha particle and then a beta particle. The final nucleus is `""_"b"^"a"` Y Find a and b.
What happens to the position of an element in the periodic table when it emits an alpha particle
During the emission of a beta particle, the ______ number remains same.
How is a zinc sulphide screen affected when a cathode ray beam strikes it?
Justify with reason, whether the following nuclear reactions are allowed or not.
\[\ce{^A_Z X -> ^A_{Z + 1}Y + ^0_{-1}β}\]
From α, β and γ-rays, name the one which travels with the speed of light?
Unit of radioactivity is _______
Which of the following statements is/are correct?
- α particles are photons
- Penetrating power of γ radiation is very low
- Ionization power is maximum for α rays
- Penetrating power of γ radiation is very high
