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 $V$)

$A$ closely wound coil of $100$ turns and of cross-section $1 \,cm^2$ has a coefficient of self-inductance $1 \,mH$. The magnetic induction at the centre of the core of the coil when a current of $2 \,A$ flows in it will be (in $Wb/m^2$):

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

An $e.m.f.$ of $5 \,V$ is produced by a self-inductance when the current changes at a steady rate from $3 \,A$ to $2 \,A$ in $1 \,ms$. The value of self-inductance is:

$A$ $10\, V$ battery connected to $5\,\Omega$ resistance coil having inductance $10\, H$ through a switch drives a constant current in the circuit. The switch is suddenly opened and the time taken to open it is $2\, ms$. The average $emf$ induced across the coil is

$A$ graph of magnetic flux $(\phi)$ versus current $(I)$ is plotted for four inductors $A, B, C, D$. Which inductor has the largest value of self-inductance?