Which of the following quantity should be increased beyond a threshold value so that a photosensitive material would emit electrons when excited by photons ?

Options

A. intensity of light
B. frequency of light
C. wavelength of light
D. voltage applied to the light source

Answer

B

Explanation

For a given metal, the maximum kinetic energy of photoelectrons varies linearly with the frequency of incident radiation. However, there is a certain limit above which the frequency must be for the electrons to be emitted. This frequency is called Threshold frequency.