A circular copper disc,$\mathrm{ }1 \mathrm{m}$ in diameter, rotates at $5 \mathrm{r}\mathrm{a}\mathrm{d} {\mathrm{s}}^{-1}$ about an axis through its centre and at right angles to disc and parallel to magnetic median. If the horizontal component of earth's magnetic field is $0.2\times {10}^{-4} \mathrm{T}$, what is the potential difference developed between the axis of the disc and the rim?

Consider the following statements:

(A) An emf can be induced by moving a conductor in a magnetic field

(B) An emf can be induced by changing the magnetic field

Consider the situation shown in figure. The wire AB is slid on the fixed rails with a constant velocity. If the wire AB is replaced by a semicircular wire, then the induced current magnitude will

A horizontal rod of length $L$ rotates about a vertical axis with a uniform angular velocity $\mathrm{\omega }$. A uniform magnetic field $B$ exists parallel to the axis of rotation. Then potential difference between the two ends of the rod is

A constant force $F$ is being applied on a rod of length $l$ kept at rest on two parallel conducting rails connected at ends by resistance $R$ in uniform magnetic field $B$ as shown,

Figure shows a square loop of side $1 \mathrm{m}$ and resistance $1 \mathrm{\Omega }$. The magnetic field on left side of line $PQ$ has a magnitude $B=1.0 \mathrm{T}$. The work done in pulling the loop out of the field uniformly in $1 \mathrm{s}$ is,