A \( p-n \) photodiode is made of a material with a band gap of \( 2 \mathrm{eV} \). The minimum...

A \( p-n \) photodiode is made of a material with a band gap of \( 2 \mathrm{eV} \). The minimum frequency of the radiation that can be absorbed by the material is nearly (Take \( h c=1240 \mathrm{eV}-\mathrm{nm}) \)
(a) \( 1 \times 10^{14} \mathrm{~Hz} \)
(b) \( 20 \times 10^{14} \mathrm{~Hz} \)
(c) \( 10 \times 10^{14} \mathrm{~Hz} \)
(d) \( 5 \times 10^{14} \mathrm{~Hz} \)