Radio frequency choke uses a core of

The current $i$ in an inductance coil varies with time $t$ according to the following graph. Which one of the following plots shows the variations of voltage $V$ in the coil?

Two inductor coils of self-inductance $3\,H$ and $6\,H$ respectively are connected with a resistance $10\,\Omega$ and a battery $10\,V$ as shown in the figure. The ratio of the total energy stored at steady state in the inductors to that of the heat developed in the resistance in $10\,s$ at the steady state is (neglect mutual inductance between $L_1$ and $L_2$):-

$A$ circular coil and a bar magnet placed nearby are made to move in the same direction. The coil covers a distance of $1\, m$ in $0.5\, s$ and the magnet covers a distance of $2\, m$ in $1\, s$. The induced emf produced in the coil is.....$V$.

Discuss the types of $AC$ generator. How much power they deliver? What is the frequency of $AC$ generator?

$AB$ is a part of an electrical circuit (see figure). The potential difference $V_{A}-V_{B}$, at the instant when current $i=2 \text{ A}$ and is increasing at a rate of $1 \text{ A/s}$, is: (in $\text{ V}$)