Plot a graph showing the variation of stopping potential with the frequency of incident radiation for two different photosensitive materials having work functions W1 and W2(W1>W2). On what factors do the (i) slope and (ii) intercept of the lines depend?
Answer: Slope =h/e (same for both); intercept =−W/e (depends on work function).
Solution
From Einstein's equation eV0=hν−W, i.e.
V0=ehν−eW,
which is a straight line y=mx+c (see figure). (i) Slope=eh — a universal constant, the same for both metals and independent of the material. (ii) Intercept on the V0-axis =−eW — depends on the work function of the metal (more negative for larger W).
