MCQ
The electrical conductivity of a semiconductor increases when electromagnetic radiation of wavelength shorter than $2480 \;nm$ is incident on it. The band gap in $(eV)$ for the semiconductor is
- A$0.9$
- B$0.7$
- ✓$0.5$
- D$1.1$
✓
Answer
Correct option: C.
$0.5$
c
$E_{g}=h v$
$E_{g}=h v$
$=\frac{h c}{\lambda}=\left(\frac{6.63 \times 10^{-34} \times 3 \times 10^{8}}{2480 \times 10^{-9} \times 1.6 \times 10^{-19}}\right) eV$
$=0.5 eV$
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
A current $I$ enters a circular coil of radius $R$, branches into two parts and then recombines as shown in the circuit diagram. The resultant magnetic field at the centre of the coil is
→Four condensers each of capacity 4μF are connected as shown in figure. $V_P-V_Q=15$ $volts$. The energy stored in the system is
→Bonds in semiconductors are :
The current in the adjoining circuit will be
Ten capacitor are joined in parallel and charged with a battery up to a potential V. They are then disconnected from battery and joined again in series then the potential of this combination will be
The kinetic energy of emitted electron is $E$ when the light incident on the metal has wavelength $\lambda$. To double the kinetic energy, the incident light must have wavelength.
→Root mean square value of ac voltage $V=$ $200 \sin \left(100 \pi t+\frac{\pi}{2}\right)$ is :
→Flint glass prism is joined by a crown glass prism to produce dispersion without deviation. The refractive indices of these for mean rays are 1.602 and 1.500 respectively. Angle of prism of flint prism is 10°, then the angle of prism for crown prism will be
A man is suffering from colour blindness for green colour. To remove this defect, he should use goggles of
The kinetic energy possessed by a body of mass $m$ moving with a velocity $ v$ is equal to $\frac{1}{2}m{v^2}$, provided
→