The mutual inductance of an induction coil is $5\,H$. In the primary coil,the current reduces from $5\,A$ to zero in $10^{-3}\,s$. What is the induced emf in the secondary coil in $V$?

Two concentric circular coils having radii $r_{1}$ and $r_{2}$ $(r_{2} \ll r_{1})$ are placed coaxially with centers coinciding. The mutual inductance of the arrangement is (Both coils have a single turn) ($\mu_{0} =$ permeability of free space).

$A$ circular loop of radius $0.3 \ cm$ lies parallel to a much bigger circular loop of radius $20 \ cm$. The centre of the smaller loop is on the axis of the bigger loop. The distance between their centres is $15 \ cm$. If a current of $2.0 \ A$ flows through the smaller loop,then the flux linked with the bigger loop is $............. \times 10^{-11} \ Wb$.

The mutual inductance of two coils is $45 \ mH$. The self-inductance of the coils are $L_1 = 75 \ mH$ and $L_2 = 48 \ mH$. The coefficient of coupling between the two coils is

The mutual inductance of two coils is $8 \ mH$. The current in one coil changes according to the equation $I = 12 \sin 100t$,where $I$ is in ampere and $t$ is time in second. The maximum value of emf induced in the second coil is (in $V$)

If a current of $3.0 \ A$ flowing in the primary coil is reduced to zero in $0.001 \ s$,then the induced $e.m.f.$ in the secondary coil is $15000 \ V$. The mutual inductance between the two coils is (in $H$):