Motional Electromotive Force

Two parallel rails of a railways track, insulated from each other and with the ground, are connected to a millivoltmeter. The distance between the rails is one metre. A train is travelling with a velocity of $72 \mathrm{km}$ ${\mathrm{h}}^{-1}$ along the track. The reading of the millivotmeter (in $\mathrm{mV}$) is (Vertical component of the earth's magnetic induction is$2\times {10}^{-5}\mathrm{T})$,

A copper rod of length $l$ is rotated about one end, perpendicular to the magnetic field $B$, with constant angular velocity $\mathrm{\omega }$. The induced emf between the two ends of the rod is,

A solid metal cube of edge length $2\mathrm{ }\mathrm{cm}$ is moving in a positive $y$ -direction at a constant speed of $6\mathrm{ }\mathrm{m}/\mathrm{s}$. There is a uniform magnetic field of $0.1\mathrm{ }\mathrm{T}$ in the positive $z$ -direction. The potential difference between the two faces of the cube perpendicular to the $x$ -axis, is:

The total charge, induced in a conducting loop, when it is moved in a magnetic field depends on

A conducting wire is moving towards right (with velocity $v$) in magnetic field $B$. If direction of induced current is as shown in figure then the direction of magnetic field is-

A conducting rod is moving with velocity $V$ in a magnetic field $B$. An emf is induced across its ends when-

A $2 \mathrm{m}$ long wire is moving with a velocity $1 \mathrm{m} {\mathrm{s}}^{-1}$ in a magnetic field of intensity $0.5 \mathrm{W}\mathrm{b} {\mathrm{m}}^{-2}$ in a direction perpendicular to the field. The emf induced in it will be,

One conducting U-tube can slide inside another as shown in figure, maintaining electrical contacts between the tubes. The magnetic field B is perpendicular to the plane of the figure. If each tube moves towards the other at a constant speed $v$, then the emf induced in the circuit in terms of $B, l \mathrm{a}\mathrm{n}\mathrm{d}\mathrm{ }v,\mathrm{ }\mathrm{w}\mathrm{h}\mathrm{e}\mathrm{r}\mathrm{e}\mathrm{ }l$ is the width of each tube, will be