Question

The electrical conductivity of a semiconductor increases when electromagnetic radiation of wavelength shorter than $2480nm$ is incident on it. The forbidden band energy for the semiconductor in $eV$ is

• A. $0.5$
• B. $0.9$
• C. $0.7$
• D. $1.1$

Answer 1

Answer: (A)

$0.5$

Given that:
The wavelength of electromagnetic radiation is $\lambda =2480nm$
The energy of electromagnetic radiation is given by
$E=\frac{hc}{\lambda }$
where, $h$ is Plank's constant and $c$ is velocity of light in nm.
Hence,
$E=\frac{1242}{2480}=0.5eV$