Question

Define the following with reference to photoelectric effect : 

(a) Threshold frequency (`f_0`)

(b) Stopping potential (`V_s`)

Answer 1

 (a) The minimum frequency of incident radiation below which photoelectric emission is not possible for a photosensitive plate of a given material, is called threshold frequency (`f_0`) .

(b) The mimimum magnitude of negative potential of the collector plate relative to the emitter plate, for which the photocurrent becomes zero, is called stopping potential (`V_s`) .