The figure shown has two coils of wires placed in close proximity. The current in primary coil $P$ is made to vary with time as shown in the graph. Which of the following graphs best represents the variation of the emf induced in the secondary coil $S$?

Which of the following is constructed on the principle of electromagnetic induction?

$A$ conducting circular loop of resistance $20 \Omega$ and cross-sectional area $20 \times 10^{-2} \,m^{2}$ is placed perpendicular to a spatially uniform magnetic field $B$, which varies with time $t$ as $B = 2 \sin(50 \pi t) \,T$. Find the net charge flowing through the loop in $20 \,ms$ starting from $t = 0$. (in $\,C$)

$A$ coil and a bulb are connected in series with a $DC$ source. $A$ soft iron core is then inserted into the coil. What happens to the intensity of the bulb?

Metal rings $P$ and $Q$ are lying in the same plane where current $I$ is increasing steadily. The induced current in the metal rings is shown correctly in which figure?

$A$ square loop of side $12 \; cm$ with its sides parallel to $X$ and $Y$ axes is moved with a velocity of $8 \; cm \, s^{-1}$ in the positive $x$-direction in an environment containing a magnetic field in the positive $z$-direction. The field is neither uniform in space nor constant in time. It has a gradient of $10^{-3} \; T \, cm^{-1}$ along the negative $x$-direction (that is, it increases by $10^{-3} \; T \, cm^{-1}$ as one moves in the negative $x$-direction), and it is decreasing in time at the rate of $10^{-3} \; T \, s^{-1}$. Determine the direction and magnitude of the induced current in the loop if its resistance is $4.50 \; m\Omega$.