Two coils have a mutual inductance of $0.005 \text{ H}$. The current changes in the first coil according to equation $I = I_0 \sin \omega t$, where $I_0 = 10 \text{ A}$ and $\omega = 60\pi \text{ rad s}^{-1}$. The maximum value of e.m.f. in the second coil in volt will be (in $\pi$)

$A$ small square loop of wire of side $l$ is placed inside a large square loop of wire $L$ $(L \gg l)$. Both loops are coplanar and their centres coincide at point $O$ as shown in the figure. The mutual inductance of the system is:

There are two long coaxial solenoids of the 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

$A$ small square loop of wire of side $l$ is placed inside a large circular loop of radius $r$. The loops are coplanar and their centers coincide. The mutual inductance of the system is proportional to

Two coils $P$ and $S$ have a mutual inductance of $\pi \text{ mH}$. The secondary coil $S$ has resistance $4 \text{ } \Omega$ and self-inductance $(60/\pi) \text{ mH}$. If the current in the primary is $I_p = 12 \sin(50\pi t)$, then the maximum value of the current induced in coil $S$ is [Take $\pi^2 = 10$] (in $\text{ A}$)

$A$ solenoid has $2000$ turns wound over a length of $0.30 \ m$. The area of its cross-section is $1.2 \times 10^{-3} \ m^2$. Around its central section,a coil of $300$ turns is wound. If an initial current of $2 \ A$ in the solenoid is reversed in $0.25 \ s$,the emf induced in the coil is equal to