Describe an experiment to study the effect of frequency of incident radiation on ‘stopping potential’

We can use the experimental arrangement to study the effect of frequency of incident radiation on stopping potential shown in fig.

Now to study the relation between frequency of the incident radiation and stopping potential, We suitably adjust the same intensity of light radiation at various frequencies and study the variation of photo current with collector plate potential. The resulting variation is as shown in the figure.

From experiment we can observe that
i) The value of stopping potential is different for radiations of different frequencies.
ii) The value of stopping potential is more for higher frequency. This implies that the value of maxi mum kinetic energy depends on the frequency of incident radiation.
iii) The value of saturation current depends on the intensity of incident radiation but is independent of the frequency of incident radiation.

iv) If a graph is drawn between the frequency of incident radiation v and the stopping potential (V₀) at constant intensity of radiation, it will be a straight line AB as shown in Fig. From the graph below v₀, no electrons are emitted and v₀ is called threshold frequency for the cathode material.