Electromagnetic Induction Ques 1
1. A $800$ turn coil of effective area $0.05$ $ m^{2}$ is kept perpendicular to a magnetic field $510^{-5}$ $T$. When the plane of the coil is rotated by $90^{\circ}$ around any of its coplanar axis in $0.1 $ $s$, the emf induced in the coil will be :
[2019]
(a) $2 $ $V$
(b) $0.2 $ $V$
(c) $2 \times 10^{-3} $ $V$
(d) $0.02 $ $V$
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Answer:
Correct Answer: 1.(d)
Solution:
- (d) Given :
Magnetic field $B=5 \times 10^{-5} $ $T$
Number of turns in coil $N=800$
Area of coil A $=0.05 $ $m^{2}$
Time taken to rotate $=\Delta t=0.1 $ $s$
Initial angle $\theta_1=0^{\circ}$
Final angle $\theta_2=90^{\circ}$
Change in magnetic flux $\Delta \phi$
$=NBA \cos 90^{\circ}-BA \cos 0^{\circ}$
$=-NBA$
$=-800 \times 5 \times 10^{-5} \times 0.05$
$=-2 \times 10^{-2}$ weber
$ \theta=-\frac{\Delta \phi}{\Delta t}=\frac{-(-) 2 \times 10^{-3} Wb}{0.1 s}=0.02 $ $V $
BETA
