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 ......... $V$.

Assertion: An $emf$ $\vec{E}$ is induced in a closed loop where magnetic flux is varied. The induced $\vec{E}$ is not a conservative field.
Reason: The line integral $\oint \vec{E} \cdot d\vec{l}$ around the closed loop is nonzero.

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?

$A$ copper ring having a cut such as not to form a complete loop is held horizontally and a bar magnet is dropped through the ring with its length along the axis of the ring as shown in figure. The acceleration of the falling magnet is ($g=$ acceleration due to gravity)

$A$ coil with an area of $500 \ cm^2$ and $1000$ turns is placed in a magnetic field of $2 \times 10^{-5} \ Wb/m^2$ perpendicular to its plane. If the coil is rotated by $180^o$ in $0.2 \ s$,the induced $emf$ in $milli-volts$ is:

Faraday's laws are a consequence of the conservation of