Advertisements
Advertisements
Question
How can they be made to leave the metal surface? (State any two ways)
Advertisements
Solution
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.
APPEARS IN
RELATED QUESTIONS
In a cathode ray tube, what is the function of anode?
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 mean by Mass number.
Draw a diagram of a simple atom showing the nucleus and electrons. In this atom:
(a) What type of charge will there be on the nucleus?
(b) What is the value of this charge?
State two characteristics of the substance used as thermionic emitter.
Justify with reason, whether the following nuclear reactions are allowed or not.
\[\ce{^A_Z X -> ^A_{Z - 2}X + ^4_{2}He}\]
An electrons emitter must have how much work function and melting point.
What is the value of the speed of gamma radiations in air or vacuum?
A deuteron strikes 8O16 nucleus with subsequent emission of an alpha particle. Identify the nucleus so produced:
