Question

At stopping potential, if the wavelength of the incident light is kept fixed at $4000\stackrel{o}{A}$, but the intensity of light increases two times, Find out the change in magnitude of stopping potential.

Answer 1

By increasing the intensity of incident radiation, only number of photons increases which results in the increase in number of photo electrons emitted but maximum kinetic of photo electrons remains the same and thus stopping potential also remains the same.
So, change in magnitude of stopping potential is zero.