Question

Explain giving reasons for the following :
(a) Photoelectric current in a photocell increases with the increase in the intensity of the incident radiation.
(b) The stopping potential $\left(V_0\right)$ varies linearly with the frequency ($\nu$) of the incident radiation for a given photosensitive surface with the slope remaining the same for different surfaces.
(c) Maximum kinetic energy of the photoelectrons is independent of the intensity of incident radiation.

Answer 1

(a) Since number of photoelectrons emitted is directly proportional to the intensity of incident radiation therefore, as intensity increases the electron-hole pairs also increase.
(b) $hv=h{v}_0{+}_e{V}_0$
${}_e{V}_0=h(v-v_0)$
$\Rightarrow$ $V_0=\frac{h}{e}(v-v_0)$

Further from graph, slope is a line which is a constant and it does not depend on $\nu$.
(c) As intensity increases, the number of photons increase but the energy remains same.