Define the terms (i) ‘cut-off voltage’ and (ii) threshold frequency’ in relation to the phenomenon of photoelectric effect.
Using Einstein’s photoelectric equation show how the cut-off voltage and threshold frequency for a given photosensitive material can be determined with the help of a suitable plot/graph.[O.D. I, II, III 2012]
(i) Cut-off voltage : The minimum negative potential ({{V}_{0}}) applied to the plate or anode (A) for which the photoelectric current just becomes zero.
(ii) Threshold frequency : The minimum frequency of incident radiation which is required to have photo electrons emitted from a given metal surface.
As per Einstein’s photoelectric equation,
