Question

In a region of 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

• A. $4\pi^2$ mA
• B. 30 mA
• C. 6 mA
• D. 200 mA

Answer 1

Answer: (C)

6 mA

Answer 2

$I_0=\frac{E_0}{R}=N\frac{BA \in}{R}$
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
$I_0=6\times10^{-3}A=6 \, mA$