There are $10$ turns in coil $M$ and $15$ turns in coil $N$ . If a current of $2\ A$ is passed through coil $M$ then the flux linked with coil $N$ is $1.8 × 10^{-3}\ Wb$ . If a current of $3\ A$ is passed through coil $N$ then flux linked with coil $M$ is

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 $emf$ inducted (in $volt$) in the secondary coil is

The mutual inductance between two coils is $1.25$ $henry$. If the current in the primary changes at the rate of $80$ $ampere/second,$ then the induced $e.m.f$ in the secondary is......$V$

What is the coefficient of mutual inductance when the magnetic flux changes by $2 \times 10^{-2}\,Wb$ and change in current is $0.01\,A$......$ henry$

Two circuits have mutual inductance of $0.1\, H$. What average $e.m.f$. is induced in one circuit when the current in the other circuit changes from $0$ to $20\, A$ in $0.02$ $s$......$V$

$A$ long straight wire is placed along the axis of a circular ring of radius $R$. The mutual inductance of this system is