Some magnetic flux is changed through a coil of resistance $10 \, \Omega$. As a result, an induced current is developed in it, which varies with time as shown in the figure (assuming a triangular pulse with base $0.1 \, s$ and height $4 \, A$). The magnitude of the change in flux through the coil in $Wb$ is:

If a copper ring is moved quickly towards the south pole of a powerful stationary bar magnet,then:

The coil of area $0.1 \ m^2$ has $500$ turns. After placing the coil in a magnetic field of strength $4 \times 10^{-4} \ Wb/m^2$,if it is rotated through $90^o$ in $0.1 \ s$,the average emf induced in the coil is......$V$

Magnetic flux linked with the coil in weber is given by the equation $\phi = 5t^2 + 6t + 11$. The e.m.f. induced in the coil in the $5^{\text{th}}$ second will be (in $\text{ V}$)

Assertion $(A)$: It is more difficult to move a magnet into a coil with more loops.
Reason $(R)$: This is because the emf induced in each current loop resists the motion of the magnet.

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: