$A$ coil of resistance $250 \Omega$ is placed in a magnetic field. If the magnetic flux $(\phi)$ linked with the coil varies with time $t$ $(s)$ as $\phi = 50t^2 + 7$,the current in the coil at $t = 4 \ s$ is: (in $A$)

In a magnetic field of $0.05\,T$,the area of a coil changes from $101\,cm^2$ to $100\,cm^2$ without changing the resistance,which is $2\,\Omega$. The amount of charge that flows during this period is:

The magnetic flux through a circuit of resistance $R$ changes by an amount $\Delta \phi$ in time $\Delta t$. Then the total quantity of electric charge $Q$ which is passing during this time through any point of the circuit is given by:

Two identical circular coils $A$ and $B$ are kept on a horizontal tube side by side without touching each other. If the current in the coil $A$ increases with time,in response,the coil $B$

The area of a coil is $A$. The coil is placed in a magnetic field which changes from $B_{0}$ to $4 B_{0}$ in time $t$. The magnitude of the induced e.m.f. in the coil will be:

$A$ long solenoid has $20$ turns per cm. $A$ small loop of area $\frac{4}{\pi} \text{ cm}^2$ is placed inside the solenoid normal to its axis. If the current carried by the solenoid changes steadily from $1.0 \text{ A}$ to $3.0 \text{ A}$ in $0.2 \text{ s}$,what is the magnitude of the induced emf in the loop while the current is changing (in $\mu \text{V}$)?