$A$ coil having an area $2\,m^2$ is placed in a magnetic field which changes from $1\,Wb/m^2$ to $4\,Wb/m^2$ in an interval of $2$ seconds. The $e.m.f.$ induced in the coil will be......$V$.

The induced emf cannot be produced by:

$A$ wire of irregular shape is turning into a circular shape in a magnetic field which is directed into the paper. The direction of the induced current is

$A$ square wire loop of side $10.0 \, cm$ is placed in a uniform perpendicular magnetic field of $20 \, T.$ The magnetic field decreases to zero in time interval $\Delta t.$ The bulb will glow with full brightness if the value of $\Delta t$ is.....$ms.$ (Assume the bulb requires $10 \, V$ to glow with full brightness.)

Write different methods to produce induced $emf$.

$A$ and $B$ are two metallic rings placed at opposite sides of an infinitely long straight conducting wire as shown. If current in the wire is slowly decreased,the direction of induced current will be