Two conducting circular loops of radii ${R_1}$ and ${R_2}$ are placed in the same plane with their centres coinciding. If ${R_1} > > {R_2}$, the mutual inductance $M$ between them will be directly proportional to

Two coil $A$ and $B$ have coefficient of mutual inductance $M = 2H$. The magnetic flux passing through coil $A$ changes by $4$ Weber in $10$ seconds due to the change in current in $B$. Then

Two conducting circular loops $A $and $B$ are placed in the same plane with their centres coinciding as shown in figure. The mutual inductance between them $1$s:

A circular loop of radius $0.3\, cm$ lies parallel to a much bigger circular loop of radius $20 \,cm$. The centre of the small loop on the axis of the bigger loop. The distance between their centres is $15\, cm$. If a current of $20\, A$ flows through the smaller loop, then the flux linked with bigger loop is

A very long straight conductor and 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 mutuaI induction

A small square loop of wire of side $\ell$ is placed inside a large square loop of wire of side $L$ $\left(\mathrm{L}=\ell^2\right)$. The loops are coplanar and therr centers coinside. The value of the mutual inductance of the system is $\sqrt{\mathrm{x}} \times 10^{-7} \mathrm{H}$, where X =___