1
COMEDK 2024 Evening Shift
+1
-0

A conducting circular loop is placed in a uniform magnetic field $$\mathrm{B}=0.125 \mathrm{~T}$$ with its plane perpendicular to the loop. If the radius of the loop is made to shrink at a constant rate of $$2 \mathrm{~mm} \mathrm{~s}^{-1}$$, then the induced emf when the radius is $$4 \mathrm{~cm}$$ is

A
$$0.52 \pi \mu V$$
B
$$20 \pi \mu V$$
C
$$\frac{2}{3}\mu V$$
D
$$\frac{3 \pi}{2} \mu V$$
2
COMEDK 2024 Evening Shift
+1
-0

A transformer of $$100 \%$$ efficiency has 200 turns in the primary and 40000 turns in the secondary. It is connected to a $$220 \mathrm{~V}$$ main supply and secondary feeds to a $$100 \mathrm{~K} \Omega$$ resistance. The potential difference per turn is

A
11 V
B
18 V
C
25 V
D
1.1 V
3
COMEDK 2024 Evening Shift
+1
-0

The current in a coil changes steadily from $$3 \mathrm{~A}$$ to $$5 \mathrm{~A}$$ in $$0.2 \mathrm{~s}$$ when an emf of $$2 \mu \mathrm{V}$$ is induced in it. The self-inductance of the coil is

A
0.2 mH
B
20 $$\mu H$$
C
2 $$\mu H$$
D
0.2 $$\mu H$$
4
COMEDK 2024 Evening Shift
+1
-0

The magnetic flux linked with a coil is given by the equation: $$\phi=8 t^2+t+10$$. The e.m.f. induced in the coil in the $$3^{\text {rd }}$$ second will be

A
49 V
B
33 V
C
16 V
D
20 V
EXAM MAP
Medical
NEET