Question

on what factors the retarding potential of photocell depends?

Answer 1

Stopping potential is the negative potential given to the opposite plate at which the electrons having the highest kinetic energy is stopped. So, is e is the charge on electron and V is the stopping potential, eV is the maximum KE of the electron.

Therefore, stopping potential eV_s = ½ m(v_max)²

Now, KE of the electron is given by Einstein’s photoelectric equation,

hν = ϕ + ½ m(v_max)²

ϕ is the work function

ν is the frequency of incident radiation

m is the mass of electron

v_max is the maximum velocity of the electron

=> hν = ϕ + eV_s

=> V_s = ϕ/e + (hν)/e

Thus the stopping potential depends on:

1. The frequency of the incident radiation, ν.
2. Work function, ϕ, of the metal