Two coaxial coils are very close to each other and their mutual inductance is $5 \,mH$. If a current $i = 50 \sin(500t) \,A$ is passed in one of the coils,then the peak value of the induced e.m.f. in the secondary coil will be ........... $V$.

In a transformer, the coefficient of mutual inductance between the primary and the secondary coil is $0.2 \, H$. When the current changes by $5 \, A/s$ in the primary, the induced $e.m.f.$ in the secondary will be......$V$

Two circular coils of radii $r_1$ and $r_2$ $(r_1 \ll r_2)$ are placed coaxially with their centers coinciding. The mutual inductance of the arrangement is

$A$ varying current at the rate of $3 \, A/s$ in a coil generates an $e.m.f.$ of $8 \, mV$ in a nearby coil. The mutual inductance of the two coils is:

Two concentric coplanar circular conducting loops have radii $R$ and $r$ $(R \gg r)$. Their mutual inductance is proportional to

The number of turns of primary and secondary coils of a transformer are $5$ and $10$ respectively and the mutual inductance of the transformer is $25\,H$. Now,the number of turns in the primary and secondary of the transformer are made $10$ and $5$ respectively. The mutual inductance of the transformer in henry will be: