The current in a coil changes from $3 \,A$ to $1 \,A$ in $0.1 \,s$ in a coil of self-inductance $8 \,mH$. The emf induced in the coil is

$A$ circular coil of radius $5\, cm$ has $500$ turns of a wire. The approximate value of the coefficient of self-induction of the coil will be:

The magnitude of the induced emf in a coil of inductance $30 \ mH$ in which the current changes from $6 \ A$ to $2 \ A$ in $2 \ s$ is: (in $V$)

$A$ graph of magnetic flux $(\phi)$ versus current $(I)$ is shown for four inductors $P, Q, R, S$. The largest value of self-inductance is for inductor:

$A$ long solenoid of $N$ turns has a self-inductance $L$ and area of cross-section $A$. When a current $i$ flows through the solenoid,the magnetic field inside it has magnitude $B$. The current $i$ is equal to:

An average induced $e.m.f.$ of $1\,V$ appears in a coil when the current in it is changed from $10\,A$ in one direction to $10\,A$ in the opposite direction in $0.5\,s$. The self-inductance of the coil is.....$mH$.