Question

During Einstein’s Photoelectric Experiment, what changes are observed when the frequency of the incident radiation is increased?

(a) The value of saturation current increases

(b) No effect

(c) The value of stopping potential increases

(d) The value of stopping potential decreases

This question was posed to me in homework.

This key question is from PhotoElectric Effect in chapter Quantum Physics of Engineering Physics I

Answer 1

Right answer is (c) The value of stopping potential increases

To explain I would say: As the frequency of the incident radiation increases, the kinetic energies of the emitted electron increase as well and therefore requires more repulsive force to be applied to stop them. Thus, the stopping potential increases.

The value of saturation current increases, as the intensity of the incident radiation, increases.

The value of stopping potential decreases, as the frequency decreases.