A metal surface is illuminated by a light of given intensity and frequency to cause photo emission. If the intensity of illumination is reduced to one – fourth of its original value, then the maximum kinetic energy of the emitted photoelectrons would become

In photoelectric emission, maximum kinetic energy of emitted photoelectrons does not depend upon the intensity of incident radiation. It depends upon the frequency of incident radiation. Hence, when intensity of incident radiation is reduced to one – fourth, then maximum kinetic energy of emitted photoelectrons remains unchanged