$A$ wire of length $L$ is bent into a semicircle and moved with a velocity $v$ in a magnetic field $B$ as shown. What is the induced $emf$ between its two ends?

$A$ conductor $ABCD$ is moving with speed $V$ along the $X$-axis in a region where the magnetic field is uniform and directed into the plane of the paper. Between which points is the maximum induced emf produced?

$A$ cycle wheel of radius $0.5 \; m$ is rotated with a constant angular velocity of $10 \; rad/s$ in a region of magnetic field of $0.1 \; T$ which is perpendicular to the plane of the wheel. The $EMF$ generated between its centre and the rim is.....$V$

Explain the motional $emf$ by the Lorentz force acting on the free charge carriers of a conductor.

Two conducting rings $P$ and $Q$ of radii $r$ and $2r$ rotate uniformly in opposite directions with centre of mass velocities $2v$ and $v$ respectively on a conducting surface $S$. There is a uniform magnetic field of magnitude $B$ perpendicular to the plane of the rings. The potential difference between the highest points of the two rings is

$A$ straight conductor of length $0.4\;m$ is moved with a speed of $7\;m/s$ perpendicular to a magnetic field of intensity $0.9\;Wb/m^2$. The induced $e.m.f.$ across the conductor will be......$V$.