The north and south poles of two identical magnets approach a coil,containing a condenser,with equal speeds from opposite sides. Then

Out of the following,which law obeys the law of conservation of energy?

The graph shows the magnitude $B(t)$ of a uniform magnetic field that exists throughout a conducting loop,perpendicular to the plane of the loop. Rank the five regions of the graph according to the magnitude of the emf induced in the loop,greatest first.

The induced $emf$ can be produced in a coil by:
$A.$ Moving the coil with uniform speed inside a magnetic field.
$B.$ Moving the coil with non-uniform speed inside a uniform magnetic field.
$C.$ Rotating the coil inside a uniform magnetic field.
$D.$ Changing the area of the coil inside a uniform magnetic field.
Choose the correct answer from the options given below:

Magnetic flux $\phi$ (in weber) linked with a closed circuit of resistance $10\, \Omega$ varies with time $t$ (in seconds) as $\phi = 5t^2 - 4t + 1$. The induced electromotive force in the circuit at $t = 0.2\, s$ is ......... $V$.

$A$ long solenoid with $15$ turns per $cm$ has a small loop of area $2.0 \; cm^{2}$ placed inside the solenoid normal to its axis. If the current carried by the solenoid changes steadily from $2.0 \; A$ to $4.0 \; A$ in $0.1 \; s$, what is the induced $emf$ in the loop while the current is changing?