$A$ horizontal straight wire $5 \ m$ long extending from east to west is falling freely at a right angle to the horizontal component of the earth's magnetic field $0.60 \times 10^{-4} \ Wb \ m^{-2}$. The instantaneous value of the emf induced in the wire when its velocity is $10 \ m \ s^{-1}$ is . . . . . . $\times 10^{-3} \ V$.

$A$ wire of length $1\,m$ is moving with a velocity of $8\,m/s$ at right angles to a magnetic field of $2\,T$. The magnitude of the induced emf between the ends of the wire will be $............\,V$.

$A$ 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.....$V$

An aeroplane having a wing span of $30 \ m$ flies due north with a speed of $170 \ m/s$. If the vertical component of the Earth's magnetic field is $B = 3.6 \times 10^{-5} \ T$, the potential difference between the tips of the wings will be: (in $mV$)

One conducting $U$ tube can slide inside another as shown in the 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 $B, l$ and $v$,where $l$ is the width of each tube,will be

$A$ copper disc of radius $0.1 \, m$ is rotated about its centre with $10 \, rev/s$ in a uniform magnetic field of $0.1 \, T$ with its plane perpendicular to the field. The emf induced across the radius of the disc is ........... $V$.