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

$A$ small square loop of wire of side $l$ is placed inside a large square loop of side $L$ $(L \gg l)$. If the loops are coplanar and their centres coincide,the mutual inductance of the system is directly proportional to :

An alternating current with an angular frequency of $\omega = 200\,rad/s$ and a peak value of $I_0 = 1\,A$,as shown in the figure,is applied to the primary coil of a transformer. If the coefficient of mutual induction between the primary and the secondary coils is $M = 1.5\,H$,the magnitude of the induced voltage in the secondary coil will be.....$V$.

$A$ very long straight conductor and an isosceles triangular conductor lie in a plane and are separated from each other as shown in the figure. If $a = 10 \ cm$,$b = 20 \ cm$,and $h = 10 \ cm$,find the coefficient of mutual induction.

Two coils $A$ and $B$ having turns $300$ and $600$ respectively are placed near each other. On passing a current of $3.0 \ A$ in coil $A$, the magnetic flux linked with coil $A$ is $1.2 \times 10^{-4} \ Wb$ and with coil $B$ it is $9.0 \times 10^{-5} \ Wb$. The mutual inductance of the system is:

Write the formula for the mutual inductance of two very long coaxial solenoids of length $l$.