Question

Figure shows a plot of stopping potential (V₀) with frequency (v) of incident radiation for two photosensitive materials M₁ and M₂. Explain

(i) Why the slope of both the lines is same ?

(ii) For which material emitted electrons have greater kinetic energy for the same frequency of incident radiation ?

Answer 1

(i) Slope of the graph between V₀ and v (from Einstein s equation) equals (h/e). Hence it does not depend on the nature of the material.

(ii) Emitted electrons have greater energy for material M₁. This is because ϕ₀ (= hv_o) has a lower value for material M₁.