Physics - Modern Physics Question with Solution | TestHub

According to Einstein's photoelectric equation, the maximum kinetic energy of emitted photoelectrons is given by $K_{\max }=h\nu -\Phi$, where $h\nu$ is the energy of the incident photon and $\Phi$ is the work function of the metal.

The stopping potential $V_0$ is related to the maximum kinetic energy by $e{V}_0=K_{\max }$. Thus, $V_0$ depends only on the frequency of the incident light and the nature of the material.

When the point source of light is moved farther from the emitting metal, the intensity of the incident light decreases (since intensity $I\propto \frac{1}{r^2}$). However, the frequency of the incident light remains unchanged.

Since the stopping potential is independent of the intensity of incident light, it will remain constant.

Answer: remain constant.