$A$ closed loop is moving with constant velocity in a uniform magnetic field as shown. The potential difference and current in element $AB$ will be:

Find out $V_A - V_B = ?$

$A$ long metal rod of length $L$ completes the circuit as shown. The area of the circuit is perpendicular to the magnetic field $B$. The total resistance of the circuit is $R$. The force needed to move the rod in the direction as shown with a constant speed $V$ is:

$A$ metal disc rotates freely between the poles of a magnet in the direction indicated. Brushes $P$ and $Q$ make contact with the center (axle) and the edge of the disc,respectively. What current,if any,flows through $R$?

$A$ $20 \ m$ long uniform copper wire held horizontally is allowed to fall under gravity $(g = 10 \ m/s^2)$ through a uniform horizontal magnetic field of $0.5 \ Gauss$ perpendicular to the length of the wire. The induced $EMF$ across the wire after it travels a vertical distance of $200 \ m$ is . . . . . . $mV$.

$A$ square metallic wire loop of side $0.1 \, m$ and resistance $1 \, \Omega$ is moved with a constant velocity in a magnetic field of $2 \, Wb/m^2$ as shown in the figure. The magnetic field is perpendicular to the plane of the loop, and the loop is connected to a network of resistances. What should be the velocity of the loop to have a steady current of $1 \, mA$ in the loop? (in $cm/sec$)