Modern Physics Ques 234
- The electrical conductivity of a semiconductor increases when electro magnetic radiation of wavelength shorter than $2480 $ $nm$ is incident on it. The band gap (in eV) for the semiconductor is
(1997C, 1M)
(a) $0.9$
(b) $0.7$
(c) $0.5$
(d) $1.1$
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Answer:
Correct Answer: 234.(c)
Solution:
- $\lambda _{\min }=2480 $ $nm=24800 $ $\AA$
$ \begin{aligned} \text { Energy }(\text { in eV }) & =\frac{12375}{\lambda}(\text { in } \AA) \\ E & =\frac{12375}{24800} eV \quad , \quad E \approx 0.5 eV \end{aligned} $
BETA
