The magnetic field in a coil of $100$ turns and $40 \text{ cm}^2$ area is increased from $1 \text{ T}$ to $6 \text{ T}$ in $2 \text{ s}$. The magnetic field is perpendicular to the coil. The $e.m.f.$ generated in it is $...... \text{ V}$.

In a coil of resistance $8 \, \Omega$,the magnetic flux due to an external magnetic field varies with time as $\phi = \frac{2}{3}(9 - t^2)$. The value of total heat produced in the coil,till the flux becomes zero,will be $.... \, J$.

The magnetic flux linked with a circuit of resistance $100\, \Omega$ increases from $10\, \text{Wb}$ to $60\, \text{Wb}$. The amount of induced charge that flows in the circuit is (in coulomb):

$A$ conducting circular coil is placed in a uniform magnetic field with the magnetic field initially directed perpendicular to the plane of the coil. In step $A$,the coil is rotated from its initial position by $60^{\circ}$ about its diameter in time $t$. In step $B$,the coil is further rotated about the same axis in the same sense by another $120^{\circ}$ in time $2t$. The ratio of the emf induced in the coil in step $A$ to that in step $B$ is:

The direction of induced e.m.f. during electromagnetic induction is given by

Derive the relation between induced charge and change in magnetic flux.