1
COMEDK 2025 Evening Shift
MCQ (Single Correct Answer)
+1
-0
A rectangular coil of 250 turns has an average area of $20 \mathrm{~cm} \times 15 \mathrm{~cm}$. The coil rotates with a speed of 60 cycles per second in a uniform magnetic field of $2 \times 10^{-2} \mathrm{~T}$ about an axis perpendicular to the field. The peak value of the induced emf is:
A
$36 \pi$ volt
B
$30 \pi$ volt
C
$18 \pi$ volt
D
$12 \pi$ volt
2
COMEDK 2025 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0
A circular coil of area $2 \sqrt{2} \mathrm{~cm}^2$ and resistance $2 \boldsymbol{\Omega}$ is arranged vertically in the east -west direction. A uniform magnetic field 0.2 T is set up across the plane in the north to east direction. Now the magnetic field is removed at a steady rate in 0.4 s What is the current developed in the coil?
A
$0.5 \times 10^{-3} A$
B
$0.5 \times 10^{-4} A$
C
$1 \times 10^{-4} A$
D
$0.5 \times 10^{-5} A$
3
COMEDK 2025 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0
A current of 2 A is passed through the primary coil. The total flux linked with the secondary coil, which is closely wound over the primary is $2000 \times 10^{-6}$ weber. What is the induced emf in the secondary if the current through the primary increases at a rate of $0.2 \mathrm{As}^{-1}$ ?
A
$2 \times 10^{-4} V$
B
$4 \times 10^{-4} V$
C
$1 \times 10^{-4} V$
D
$8 \times 10^{-4} V$
4
COMEDK 2025 Morning Shift
MCQ (Single Correct Answer)
+1
-0
The magnetic flux $\phi$ through a stationary loop of wire having a resistance R varies with time as $\phi=4 t^2+3 t$. The average emf and total charge flowing in the loop in the time interval $t=0$ to $t=\tau$ respectively are
A
$\tau+3, \quad \frac{4 \tau^2+3 \tau}{R}$
B
$3 \tau+4, \quad \frac{4 \tau^2+3 \tau}{R}$
C
$4 \tau+3, \quad \frac{4 r+3}{R}$
D
$4 \tau+3, \quad \frac{4 \tau^2+3 \tau}{R}$
COMEDK Subjects
EXAM MAP