The magnitude of flux linked with a coil varies with time as $\phi = 3t^2 + 4t + 7$. The magnitude of the induced e.m.f. at $t = 2 \ s$ is: (in $V$)

$A$ space consists of two uniform magnetic fields,as shown. $A$ conducting circular loop is placed symmetrically at the boundary.

The diagram below shows two circular loops of wire ($A$ and $B$) centred on and perpendicular to the $X$-axis and oriented with their planes parallel to each other. The $Y$-axis passes vertically through loop $A$ (dashed line). There is a current $I_B$ in loop $B$ as shown in the diagram. Possible actions which we might perform on loop $A$ are:
$(I)$ move $A$ to the right along $X$-axis closer to $B$
$(II)$ move $A$ to the left along $X$-axis away from $B$
$(III)$ as viewed from above,rotate $A$ clockwise about $Y$-axis
$(IV)$ as viewed from above,rotate $A$ anti-clockwise about $Y$-axis
Which of the actions will induce a current in $A$ only in the direction shown?

$A$ coil of circular cross-section having $1000$ turns and $4 \, cm^2$ face area is placed with its axis parallel to a magnetic field which decreases by $10^{-2} \, Wb \, m^{-2}$ in $0.01 \, s$. The $e.m.f.$ induced in the coil is....$mV$

$A$ long solenoid having $100$ turns per $cm$ carries a current of $\frac{4}{\pi} \,A$. At the centre of it is placed a coil of $200$ turns of cross-sectional area $25 \,cm^2$ having its axis parallel to the field produced by the solenoid. When the direction of the current in the solenoid is reversed within $0.04 \,s$, the induced emf in the coil is (in $\,V$)

The magnitude of induced emf is directly proportional to the rate of change of magnetic flux linked with the coil. This statement is known as