Physics - Modern Physics Question with Solution | TestHub

Initial frequency of incident light, ${\nu }_1=3{\nu }_0$, where ${\nu }_0$ is the threshold frequency.

New frequency of incident light, ${\nu }_2=\frac{1}{3}{\nu }_1=\frac{1}{3}(3{\nu }_0)={\nu }_0$.

Since the new incident frequency is exactly equal to the threshold frequency, the maximum kinetic energy of the emitted photoelectrons is zero ($K_{max}=h{\nu }_2-h{\nu }_0=0$).

As the photoelectrons have zero kinetic energy, they do not move towards the collector plate. Therefore, the photoelectric current will be zero, regardless of the increase in intensity.

Answer: be zero