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 ....... $V$.

Two square wire frames $abcd$ and $efgh$ are placed in a uniformly decreasing magnetic field as shown in the figure. The direction of the induced current in both the loops is

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

Faraday's laws are a consequence of the conservation of

$A$ copper rod is moved in a magnetic field. The charge developed across its ends will be proportional to

$A$ coil has $200$ turns and an area of $70 \ cm^2$. The magnetic field perpendicular to the plane of the coil is $0.3 \ Wb/m^2$ and it takes $0.1 \ s$ to rotate through $180^o$. The value of the induced $e.m.f.$ will be ...... $V$.