Physics

Physics

Problem

(a) Define the terms (i) work function and (ii) threshold frequency for a metal surface. (b) Show that for any metal the threshold wavelength λ0\lambda_0 is inversely proportional to its work function ϕ\phi. (c) A set of experimental readings of stopping potential V0V_0 versus frequency ν\nu for a clean metallic surface produces a straight-line graph that meets the frequency axis at 5.0×1014 Hz5.0\times10^{14}\,\text{Hz}. Explain qualitatively how this intercept enables one to determine the work function of the metal and state its numerical value (in eV) without using Planck’s constant.

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