Radiations of photon energies 1 eV and 2.5 eV illuminate a metal of work function 0.5 eV. Ratio of maximum electron speeds is:
Options

Question

Radiations of photon energies 1 eV and 2.5 eV illuminate a metal of work function 0.5 eV. Ratio of maximum electron speeds is:

G1 Physics · Accepted Answer

K₁ = 1 − 0.5 = 0.5 eV and K₂ = 2.5 − 0.5 = 2.0 eV. As v ∝ √K, v₁/v₂ = √(0.5/2.0) = 1/2. Answer: B.