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 $25\,henry$. 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

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

There are two long co -axial solenoids of same length $l.$ The inner and outer coils have radii $r_1$ and $r_2$ and number of turns per unit length $n_1$ and $n_2$ respectively. The ratio of mutual inductance to the self -inductance of the inner -coil is

Derive formula for mutual inductance for two very long coaxial solenoids. Also discuss reciprocity theorem.

A pair of adjacent coils has a mutual inductance of $1.5\; H$. If the current in one coil changes from $0$ to $20\; A$ in $0.5\; s ,$ what is the change of flux (in $Wb$) linkage with the other coil?

The pointer of a dead-beat galvanometer gives a steady deflection because