Question

Write Einstein’s photoelectric equation in terms of the stopping potential and the threshold frequency for a given photosensitive material. Draw a plot showing the variation of stopping potential vs the frequency of incident radiation.

Answer 1

From Einstein’s photoelectric equation, we have

(K.E.)_max = hv - W ...........(1)

If V₀ is stopping potential and v₀ is threshold frequency, then

[K.E.]_max = eV₀ and W = hv₀

So eq. (1) becomes eV₀ = hv - hv₀ = h (v - v₀)

This is Einstein’s photoelectron equation in terms of the stopping potential and the threshold frequency graph between stopping potential and the frequency of incident radiation v is given in Fig.