Answer:
(a) The greater the frequency of the incident light is, the greater is the stopping potential.
Explanation:
The stopping potential is crucial to terminate the braking of the photoemitted electrons, stopping the current completely.
Since the kinetic energy of electrons depends on the light's incidence frequency (rather than the intensity), therefore, the stopping potential is proportional to the light's incidence frequency.
The cutoff frequency, in turn, is a limiting frequency below which no photoelectric effect occurs. The cutoff frequency depends on the material from which it is made the emitting surface (and its work function).
