In the given figure,the magnet is moved towards the coil with speed $v$ and the induced $emf$ is $e$. If the magnet and the coil recede away from one another,each moving with speed $v$,the induced $emf$ in the coil will be

The magnetic flux through a coil is $4 \times 10^{-4} \ Wb$ at time $t=0$. It reduces to $30 \%$ of its original value in time $t$ seconds. If the e.m.f. induced in the coil is $0.56 \ mV$,then the value of $t$ is: (in $s$)

$A$ circular loop of radius $7 \ cm$ is placed in a uniform magnetic field of $0.2 \ T$ directed perpendicular to the plane of the loop. The loop is converted into a square loop in $0.5 \ s$. The $EMF$ induced in the loop is . . . . . . $mV$.

$A$ coil of surface area $200 \ cm^2$ having $25$ turns is held perpendicular to the magnetic field of intensity $0.02 \ Wb/m^2$. The resistance of the coil is $1 \ \Omega$. If it is removed from the magnetic field in $1 \ s$,the induced charge in the coil is . . . . . . $C$.

$A$ coil having $500$ square loops each of side $10\, cm$ is placed normal to a magnetic flux which increases at the rate of $1.0\, T/s$. The induced $e.m.f.$ in volts is:

The law of electromagnetic induction has been used in the construction of