$A$ coil has $1,000$ turns and $500 \, cm^2$ as its area. The plane of the coil is placed at right angles to a magnetic induction field of $2 \times 10^{-5} \, Wb/m^2$. The coil is rotated through $180^o$ in $0.2 \, s$. The average $e.m.f.$ induced in the coil,in milli-volts,is

Discuss Faraday's experiment of two coils for the generation of electric current in a coil.

The magnetic flux through a coil of resistance $R$ changes by an amount $\Delta \phi$ in time $\Delta t$. The amount of induced current and induced charge in the coil are respectively:

State Lenz's law and prove that it is a specific representation of the law of conservation of energy.

As shown in the figure, two identical conducting rings of radius $r$ are placed in a magnetic field. In figure $(a)$, the magnetic field is increasing at the rate of $0.3 \text{ T/s}$, and in figure $(b)$, the magnetic field is decreasing at the rate of $0.2 \text{ T/s}$. The direction of the current in ring $(a)$ and ring $(b)$, when observed from the top, is . . . . . .

Suppose a long solenoid of $100 \ cm$ length, radius $2 \ cm$ having $500 \ turns/cm$ carries a current $I = 10 \sin(\omega t) \ A$, where $\omega = 1000 \ rad/s$. $A$ circular conducting loop $(B)$ of radius $1 \ cm$ is coaxially placed inside the solenoid. The r.m.s. current through the loop when the coil $B$ is inside the solenoid is $\alpha / \sqrt{2} \ \mu A$. The value of $\alpha$ is . . . . . . . [Resistance of the loop $= 10 \ \Omega$]