Question

The threshold frequency of a metal surface for the photoelectric effect corresponds to green light. If blue light is shined on this metal

• A. no electrons will be emitted from the metal.
• B. the number of emitted electrons will be proportional to the brightness (intensity) of the blue light.
• C. the electrons will have no kinetic energy.
• D. more electrons will be emitted than if green light were shined on the metal
• E. electrons will be emitted from the metal, but since the light a not green, only a few electrons will be released.

Answer 1

The correct option is B the number of emitted electrons will be proportional to the brightness (intensity) of the blue light.

Blue light has higher frequency than that of green light. Hence the photon of blue light have sufficient energy to overcome the work potential of the metal surface. Now once the emission is possible, the photoelectric current, or the number of emitted electrons would be proportional to the intensity of the incident light.