When the switch is closed in the primary circuit,the instantaneous induced current in the secondary circuit is:

Assertion : Faraday's laws are consequences of conservation of energy.
Reason : In a purely resistive $A.C.$ circuit,the current lags behind the $e.m.f.$ in phase.

The magnetic flux linked with a coil satisfies the relation $\phi = 4t^2 + 6t + 9 \text{ Wb}$, where $t$ is the time in seconds. The emf induced in the coil at $t = 2 \text{ s}$ is (in $\text{ V}$)

Two identical circular loops of metal wire are lying on a table without touching each other. Loop $A$ carries a current which increases with time. In response,the loop $B$:

$A$ long solenoid of diameter $0.1\, m$ has $2 \times 10^4$ turns per meter. At the centre of the solenoid,a coil of $100$ turns and radius $0.01\, m$ is placed with its axis coinciding with the solenoid axis. The current in the solenoid reduces at a constant rate to $0\, A$ from $4\, A$ in $0.05\, s$. If the resistance of the coil is $10\pi^2\, \Omega$,the total charge flowing through the coil during this time is:

In a coil of resistance $8 \, \Omega$,the magnetic flux due to an external magnetic field varies with time as $\phi = \frac{2}{3}(9 - t^2)$. The value of total heat produced in the coil,till the flux becomes zero,will be $.... \, J$.