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The maximum kinetic energy of the radiated electrons is given by K_max = hc/λ - W.

1. 12375 / λ (in Å) - 5.01
2. 12375 / 2000 - 5.01 = 6.1875 - 5.01 = 1.17775
3. 1.2V
4. The potential difference that must be applied to stop photoelectrons = -1.2V

Correct answer: 12375 / λ (in Å) - 5.01

Solution

The equation K_max = hc/λ - W represents the photoelectric equation, where hc/λ is the energy of the incident photon and W is the work function. Option A correctly expresses the maximum kinetic energy in terms of wavelength (λ in Å) and work function.

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