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.

$A$ coil of resistance $200 \Omega$ is placed in a magnetic field. If the magnetic flux $\phi$ (in weber) linked with the coil varies with time $t$ (in second) as per the equation $\phi = 50t^2 + 4$,then the current induced in the coil at a time $t = 2 \ s$ is (in $A$)

As a result of a change in the magnetic flux linked to the closed loop as shown in the figure,an $e.m.f.$ $V$ volt is induced in the loop. The work done (in joule) in taking a charge $Q$ coulomb once along the loop is

$A$ hundred turns of insulated copper wire are wrapped around an iron cylinder of area $1 \times 10^{-3} \ m^2$ and are connected to a resistor. The total resistance in the circuit is $10 \ \Omega$. If the longitudinal magnetic induction in the iron changes from $1 \ Wb/m^2$ in one direction to $1 \ Wb/m^2$ in the opposite direction,how much charge flows through the circuit?

$A$ conducting loop is placed in a uniform magnetic field with its plane perpendicular to the field. An $emf$ is induced in the loop if

Lenz's law applies to