JEE Physics 2023 Question with Solution

Given: Statements about the photoelectric effect are to be checked.

Find: Which statement among A, B, C, D is correct.

For the stopping potential,

and from Einstein's photoelectric equation,

So the stopping potential depends on both the frequency of incident light and the work function of the metal. Therefore, Statement A is false.

The saturation current increases when the intensity of incident light increases, because higher intensity means more photons strike the surface per unit time and hence more photoelectrons are emitted. Therefore, Statement B is true.

Again using

the maximum kinetic energy depends on the frequency of incident light and the work function, not on the intensity. Therefore, Statement C is false.

The wave theory of light cannot explain key observations of the photoelectric effect such as threshold frequency and instantaneous emission. The effect is explained by the particle nature of light. Therefore, Statement D is false.

Only Statement B is correct. Hence, the correct option is C.

Statement A: The claim says stopping potential depends only on work function. But

Hence stopping potential depends on both $\nu$ and $\phi$. So this statement is false.

Statement B: Saturation current is related to the number of emitted photoelectrons. Increasing light intensity increases the number of incident photons per unit time, so the emitted photoelectrons and hence the saturation current increase. So this statement is true.

Statement C: The maximum kinetic energy is fixed by the photon energy and work function:

Intensity changes the number of emitted electrons, not their maximum kinetic energy. So this statement is false.

Statement D: Classical wave theory fails to explain the photoelectric effect completely. The correct explanation requires photons and quantized energy. So this statement is false.

Therefore, only B is correct, which corresponds to option C in the given list.