Semiconductor Electronics Materials Devices And Simple Circuits Ques 30
30. A p-n photodiode 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
[2008]
(a) $10 \times 10^{14}$ $ Hz$
(b) $5 \times 10^{14}$ $ Hz$
(c) $1 \times 10^{14}$ $ Hz$
(d) $20 \times 10^{14}$ $ Hz$
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Answer:
Correct Answer: 30.(b)
Solution:
- (b) $E_g=2.0 eV=2 \times 1.6 \times 10^{-19} $ $J$
$E_g=h v$
$\therefore v=\frac{E_g}{h}=\frac{2 \times 1.6 \times 10^{-19} J}{6.62 \times 10^{-34} Js}$
$=0.4833 \times 10^{15} s^{-1}=4.833 \times 10^{14} Hz \simeq 5 \times 10^{14}$ $ Hz$
BETA
