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

The magnetic flux through a coil of resistance $10\,\Omega$ is changed by $\Delta \phi$ in $0.1\,s$. The resulting current in the coil varies with time as shown in the figure. Then,the magnitude $\left| \Delta \phi \right|$ is equal to (in weber):

On which factor does the induced charge depend?

There are two coils $A$ and $B$ as shown in the figure. No current flows in $B$ if $A$ is at rest. Now,the coil $A$ is made to rotate about a vertical axis. At the shown instant $(t=0)$,what will be the direction of the current in coil $A$,when the induced current in coil $B$ is counterclockwise?

Consider a metal ring kept (supported by a cardboard) on top of a fixed solenoid carrying a current $I$ as per the figure. The centre of the ring coincides with the axis of the solenoid. If the current in the solenoid is switched off,what will happen to the ring?

The north pole of a magnet is brought near a metallic ring. The direction of the induced current in the ring will be