1
COMEDK 2025 Morning Shift
MCQ (Single Correct Answer)
+1
-0
The electrical conductivity of a semiconductor increases when electromagnetic radiation of wavelength shorter than $1.24 \mu \mathrm{~m}$ is incident on it. The band gap (in eV ) for the semiconductor is
A
1 eV
B
1.1 eV
C
2.48 eV
D
0.7 eV
2
COMEDK 2025 Morning Shift
MCQ (Single Correct Answer)
+1
-0
In a nuclear fusion reaction, two nuclei, $A$ and $B$ fuse to produce a nucleus $C$, releasing an amount of energy $\Delta \mathrm{E}$ in the process. If the mass defects of the three nuclei are $\Delta M_A, \Delta M_B$ and $\Delta M_C$ respectively, then which of the following relations is true? ( $c$ is the speed of light).
A
$\Delta M_A+\Delta M_B=\Delta M_C+\frac{\Delta E}{c^2}$
B
$\Delta M_A-\Delta M_B=\Delta M_C+\frac{\Delta E}{c^2}$
C
$\Delta M_A-\Delta M_B=\Delta M_C-\frac{\Delta E}{c^2}$
D
$\Delta M_A+\Delta M_B=\Delta M_C-\frac{\Delta E}{c^2}$
3
COMEDK 2025 Morning Shift
MCQ (Single Correct Answer)
+1
-0

In the energy band diagram of a material shown below, open circles and filled circles denote holes and electrons respectively. The material is a

COMEDK 2025 Morning Shift Physics - Semiconductor Devices and Logic Gates Question 1 English

A
metal
B
insulator
C
n-type semiconductor
D
p-type semiconductor
4
COMEDK 2025 Morning Shift
MCQ (Single Correct Answer)
+1
-0
A particle moves towards west with a velocity of $10 \mathrm{~ms}^{-1}$. After 10s its direction changes towards south and it moves with the same velocity. The average acceleration of the particle is:
A
$2 \sqrt{2} m s^{-2} N E$
B
$\left(\frac{1}{\sqrt{2}}\right) m s^{-2} S E$
C
$2 m s^{-2} N E$
D
$\sqrt{2} m s^{-2} S E$
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