$A$ 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:

$A$ rod of length $1.0 \,m$ is rotated in a plane perpendicular to a uniform magnetic field of induction $0.25 \,T$ with a frequency of $12 \,rev/s$. The induced emf across the ends of the rod is (in $\,V$)

Prove that the mechanical power required to move a rod in a uniform magnetic field is converted into electrical power.

$A$ conducting wire is dropped along the east-west direction. Then,

$A$ rod of length $l$ is rotated with angular velocity $\omega$ about one of its ends,in a region perpendicular to a uniform magnetic field of induction $B$. The induced e.m.f. in the rod is:

$A$ $20\,cm$ long metallic rod is rotated with $210\,rpm$ about an axis normal to the rod passing through its one end. The other end of the rod is in contact with a circular metallic ring. $A$ constant and uniform magnetic field of $0.2\,T$ parallel to the axis exists everywhere. The emf developed between the centre and the ring is $.......\,mV$. Take $\pi=\frac{22}{7}$.