A small square loop of wire of side $l$ is placed inside a large square loop of wire of side $(L > l)$. The loop are coplanar and their centre coincide. The mutual inductance of the system is proportional to
$l / L$
${l^2}/L$
$L/l$
${L^2}/l$
An $e.m.f.$ of $100\,millivolts$ is induced in a coil when the current in another nearby coil becomes $10\, ampere$ from zero in $0.1\,second$ . The coefficient of mutual induction between the two coils will be.....$millihenry$
Two coils of self inductance $2\,\,mH$ and $8\,\,mH$ are placed so close together that the effective flux in one coil is completely linked with the other. The mutual inductance between these coils is......$ mH$
$AB$ is an infinitely long wire placed in the plane of rectangular coil of dimensions as shown in the figure. Calculate the mutual inductance of wire $AB$ and coil $PQRS$
Two circular coils can be arranged in any of the three situations shown in the figure. Their mutual inductance will be
$A$ long straight wire is placed along the axis of a circular ring of radius $R$. The mutual inductance of this system is