Alternating Current Ques 4
4. In a region of uniform magnetic induction $B=10^{-2}$ tesla, a circular coil of radius $30 $ $cm$ and resistance $\pi^{2} ohm$ is rotated about an axis which is perpendicular to the direction of $B$ and which forms a diameter of the coil. If the coil rotates at $200 $ $rpm$ the amplitude of the alternating current induced in the coil is
[1988]
(a) $4 \pi^{2}$ $ mA$
(b) $30$ $ mA$
(c) $6$ $ mA$
(d) $200$ $ mA$
Show Answer
Answer:
Correct Answer: 4.(c)
Solution:
- (c) $I_0=\frac{E_0}{R}=\frac{n B A \omega}{R}$
Given, $n=1, B=10^{-2} $ $T$,
$A=\pi(0.3)^{2} m^{2}, R=\pi^{2}$
$f=(200 / 60)$ and $\omega=2 \pi(200 / 60)$
Substituting these values and solving, we get $I_0=6 \times 10^{-3} A=6 $ $mA$
BETA
