A p-n photo diode is made of a material with a band gap

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A p-n photo diode is made of a material with a band gap of 2.0 eV. The minimum frequency of the radiation that can be absorbed by the material is nearly

1. 10 × 10¹⁴ Hz
2. 5 ×10¹⁴ Hz
3. 1 × 10¹⁴ Hz
4. 20 × 10¹⁴ Hz

Correct Option: B

E_g = 2.0 eV = 2 × 1.6 × 10^–19 J
E_g = hv

∴ v =	E_g	=	2 × 1.6 × 10^-19 J
	h		6.62 × 10^-34 Js

= 0.4833 × 10¹⁵ s^-1 = 4.833 × 10¹⁴ Hz
≃ 5 × 10¹⁴