A big circular coil with \(1000\) turns and an average radius of \(10~\text{m}\) is rotating about its horizontal diameter at a rate of \(2~\text{rad s}^{-1}.\) The vertical component of the Earth's magnetic field at that location is \(2\times 10^{-5}~\text{T},\) and the electrical resistance of the coil is \(12.56~\Omega,\) the maximum induced current in the coil will be:
1. \(2~\text{A}\)
2. \(0.25~\text{A}\)
3. \(1.5~\text{A}\)
4. \(1~\text{A}\)

The current in an inductor of self-inductance \(4~\text{H}\) changes from \(4~ \text{A}\) to \(2~\text{A}\) in \(1~ \text s\). The emf induced in the coil is:
1. \(-2~\text{V}\)
2. \(2~\text{V}\)
3. \(-4~\text{V}\)
4. \(8~\text{V}\)

The dimensions of mutual inductance \((M)\) are:
1. \(\left[M^2LT^{-2}A^{-2}\right]\)
2. \(\left[MLT^{-2}A^{2}\right]\)
3. \(\left[M^{2}L^{2}T^{-2}A^{2}\right]\)
4. \(\left[ML^{2}T^{-2}A^{-2}\right]\)

Two conducting circular loops of radii \(R_1\)$\mathrm{and}$\(R_2\) are placed in the same plane with their centres coinciding. If \(R_1>>R_2\) the mutual inductance \(M\) between them will be directly proportional to:

For a coil having \(L=2~\text{mH},\) the current flow through it is \(I=t^2e^{-t}.\) The time at which emf becomes zero is:
1. \(2\) s
2. \(1\) s
3. \(4\) s
4. \(3\) s