The light of two different frequencies whose photons have energies 3.8 eV and 1.4 eV respectively, illuminate a metallic surface whose work function is 0.6 eV successively. The ratio of maximum speeds of emitted electrons for the two frequencies respectively will be:
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Question

The light of two different frequencies whose photons have energies 3.8 eV and 1.4 eV respectively, illuminate a metallic surface whose work function is 0.6 eV successively. The ratio of maximum speeds of emitted electrons for the two frequencies respectively will be:

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G1 Physics · Accepted Answer

Step 1: Photon energy is Eγ = hc/λ and Einstein's equation is Kₘₐₓ = Eγ−φ. Step 2: If a stopping potential is involved, Kₘₐₓ = eVₛ. Step 3: Using the two stated cases eliminates φ or gives it directly. Final: B: 2 : 1.