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

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 coaxial solenoids are made by winding thin insulated wire over a pipe of cross-sectional area $A = 10\ cm^2$ and length$= 20\ cm$. If one of the solenoid has $300$ turns and the other $400$ turns, their mutual inductance is

$\mu_{0}=4 \pi \times 10^{-7} \;TmA ^{-1}$

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 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:

Two conducting circular loops of radii $R_{1}$ and $\mathrm{R}_{2}$ 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: