(a(i))[2]
Explain what the term photon means.
(a(ii))[1]
By referring to the intensity of light, state one item of evidence from the photoelectric effect that supports a particulate nature of light.
(b)[5]
Some electron energy levels in a solid are shown in Fig. 11.1. A semiconductor material has a very high resistance in darkness. Light falling on the semiconductor material makes its resistance fall. Explain the resistance of the semiconductor material under different light conditions.