$A$ coil having $500$ square loops each of side $10 \ cm$ is placed normal to a magnetic flux which increases at a rate of $1 \ T s^{-1}$. The induced emf is (in $V$)

The coil of a dynamo is rotating in a magnetic field. The developed induced $e.m.f.$ changes and the number of magnetic lines of force also changes. Which of the following conditions is correct?

In a closed circuit, there is only a coil of inductance $L$ and resistance $100 \Omega$. The coil is situated in a uniform magnetic field. Suddenly, the magnetic flux linked with the circuit changes by $5 \text{ Wb}$. What amount of charge will flow in the circuit as a result?

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 $\text{ V}$)

Three identical coils $C_1, C_2$ and $C_3$ are placed coaxially. $C_2$ is exactly midway between $C_1$ and $C_3$. $C_1$ carries current $I$ in an anti-clockwise direction, while $C_3$ carries current $I$ in a clockwise direction. An induced current flows through $C_2$ in a clockwise direction when:

Assertion : An induced current has a direction such that the magnetic field due to the current opposes the change in the magnetic flux that induces the current.
Reason : The above statement is in accordance with the conservation of energy.