The radius of the circular conducting loop shown in the figure is $R.$ The magnetic field is decreasing at a constant rate $\alpha.$ The resistance per unit length of the loop is $r.$ Find the current in the wire $AB,$ where $AB$ is one of the diameters.

$A$ time-varying magnetic field $B(t)$ exists in a circular region of radius '$a$' and is directed into the plane of the paper,as shown in the figure. The magnitude of the induced electric field at a point '$P$' at a distance '$r$' $(r > a)$ from the center of the circular region is:

$A$ uniform magnetic field $B$ exists in a cylindrical region of radius $10\,cm$ as shown in the figure. $A$ uniform wire of length $80\,cm$ and resistance $4.0\,\Omega$ is bent into a square frame and is placed with one side along a diameter of the cylindrical region. If the magnetic field increases at a constant rate of $0.010\,T/s$,find the current induced in the frame.

Consider an infinitely long wire carrying a current $I(t)$,with $\frac{dI}{dt} = \lambda = \text{constant}$. Find the current produced in the rectangular loop of wire $ABCD$ if its resistance is $R$ as shown in the figure.

$A$ uniform magnetic field $B$ exists in a direction perpendicular to the plane of a square loop made of a metal wire. The wire has a diameter of $4 \, mm$ and a total length of $30 \, cm$. The magnetic field changes with time at a steady rate $dB/dt = 0.032 \, T s^{-1}$. The induced current in the loop is close to $.... A$ (Resistivity of the metal wire is $1.23 \times 10^{-8} \, \Omega m$).

$A$ magnetic field given by $B(t) = (0.2t - 0.05t^2) \text{ T}$ is directed perpendicular to the plane of a circular coil containing $25$ turns of radius $1.8 \text{ cm}$ and whose total resistance is $5 \Omega$. The power dissipation at $3 \text{ s}$ is nearly: (in $\text{ } \mu\text{W}$)