If the coefficient of mutual induction of the primary and secondary coils of an induction coil is $5\, H$ and a current of $10\, A$ is cut off in $5\times10^{-4}\, s$,the $emf$ induced (in $volt$) in the secondary coil is

Two coils $A$ and $B$ have mutual inductance $0.008 \ H$. The current changes in the coil $A$, according to the equation $I = I_{m} \sin \omega t$, where $I_{m} = 5 \ A$ and $\omega = 200 \pi \ rad \ s^{-1}$. The maximum value of the e.m.f. induced in the coil $B$ in volt is (in $\pi$)

Find the mutual inductance between two coaxial circular loops of radius $a$ separated by a distance $l$,where $l >> a$.

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 $V$?

The device that does not work on the principle of mutual induction is

When magnetic flux changes from $6.5 \times 10^{-2} \ Wb$ to $11 \times 10^{-2} \ Wb$ and the change in current is $0.03 \ A$,the coefficient of mutual inductance will be: (in $H$)