If the flux associated with a coil of $60$ turns varies at the rate of $1 \text{ Wb/hour}$,the induced emf is . . . . . . .

Three identical coils $C_1, C_2$ and $C_3$ are placed coaxially. $C_2$ is exactly midway between $C_1$ and $C_3$. $C_1$ carries current $I$ in an anti-clockwise direction,while $C_3$ carries current $I$ in a clockwise direction. An induced current flows through $C_2$ in a clockwise direction when:

Consider a metal ring kept on top of a fixed solenoid (say on a cardboard) as per the figure. The center of the ring coincides with the axis of the solenoid. If the current is suddenly switched on,the metal ring jumps up. Explain.

Magnetic flux (in $Wb$) linked with a closed loop varies with time $t$ (in $s$) as $\phi = 2t^2 + 1$. The magnitude of induced emf at $t = 1 \ s$ is $..... \ V$.

$A$ 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

$A$ coil of resistance $400 \Omega$ is placed in a magnetic field. If the magnetic flux $\phi$ (Wb) linked with the coil varies with time $t$ $(s)$ as $\phi = 50t^2 + 4$,the current in the coil at $t = 2 \ s$ will be: (in $A$)