If a coil of metal wire is kept stationary in a non-uniform magnetic field, then

Lenz's law applies to

$A$ vertical bar magnet is dropped from the shown position on the axis of a fixed metallic coil as shown in Fig-$I$. In Fig-$II$,the magnet is fixed and a horizontal coil is dropped. If the acceleration of the magnet and coil are $a_1$ and $a_2$ respectively,then:

$A$ metallic loop is placed in a uniform magnetic field $B$ with the plane of the loop perpendicular to $B$. Under which condition will an electromotive force (emf) be induced in the loop? "If the loop is ....."

Derive the formula for induced charge and prove that it is independent of the rate of change of magnetic flux.

The flux linked with a coil at any instant $t$ is given by $\phi = 10t^2 - 50t + 250$. The induced $emf$ at $t = 3 \ s$ is ....... $V$.