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 ....... $V$.

$A$ flexible circular loop $20 \ cm$ in diameter lies in a magnetic field of magnitude $B = 1 \ T$,directed into the plane of the page as shown. The loop is pulled at the points indicated by the arrows,forming a loop of zero area in $0.314 \ s$. The average emf induced in the loop is.....$V$

Assertion : Faraday's laws are a consequence of the conservation of energy.
Reason : In a purely resistive $AC$ circuit,the current lags behind the $emf$ in phase.

To induce an $e.m.f.$ in a coil, the linking magnetic flux

$A$ bar magnet falls with its north pole pointing down through the axis of a copper ring. When viewed from above,the current in the ring will be

If the flux associated with a coil of $60$ turns varies at the rate of $1 \text{ Wb/hour}$,the induced emf is . . . . . . .