A cadmium sulfide photodetector is irradiated over a receiving area of 4 x 10-2 cm2 by light of wavelength 0.4 x 10-6 m and intensity of 20 W m- 2 .
(a) If the energy gap of cadmium sulfide is 2.4 eV, confirm that electron-hole pairs will be generated.
(b) Assuming each quantum generates an electron-hole pair, calculate the number of pairs generated per second.