$A$ coil of $45$ turns and radius $4 \ cm$ is placed in a uniform magnetic field such that its plane is perpendicular to the direction of the field. If the magnetic field increases from $0$ to $0.70 \ T$ at a constant rate in a time interval of $220 \ s$,then the induced emf in the coil is (in $mV$)

The charge which will flow through a galvanometer of resistance $200 \Omega$ connected to a $400 \Omega$ circular coil of $1000$ turns wound on a wooden stick $20 \ mm$ in diameter,if a magnetic field $B=0.012 \ T$ parallel to the axis of the stick is decreased suddenly to zero,is nearly: (in $\mu C$)

$A$ square wire loop of $10.0 \, cm$ side lies at right angles to a uniform magnetic field of $20 \, T$. $A$ $10 \, V$ light bulb is in series with the loop as shown in the figure. The magnetic field is decreasing steadily to zero over a time interval $\Delta t$. The bulb will shine with full brightness if $\Delta t$ is equal to.......$ms$.

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:

Consider a metal ring kept on top of a fixed solenoid (say on a cardboard) as per the figure. The center of the ring coincides with the axis of the solenoid. If the current is suddenly switched on,the metal ring jumps up. Explain.

$A$ square loop of side $10 \ cm$ and resistance $0.7 \ \Omega$ is placed vertically in the east-west plane. $A$ uniform magnetic field of $0.20 \ T$ is set up across the plane in the north-east direction. The magnetic field is decreased to zero in $1 \ s$ at a steady rate. Then,the magnitude of the induced emf is $\sqrt{x} \times 10^{-3} \ V$. The value of $x$ is . . . . . . .