The magnetic flux through a loop of resistance $10 \Omega$ is given by $\phi = 5t^2 - 4t + 1 \text{ Wb}$. How much current is induced in the loop after $0.2 \text{ s}$ (in $\text{ A}$)?

It is desired to measure the magnitude of the magnetic field between the poles of a powerful loudspeaker magnet. $A$ small flat search coil of area $2 \; cm^{2}$ with $25$ closely wound turns is positioned normal to the field direction and then quickly snatched out of the field region. (Equivalently,one can give it a quick $90^{\circ}$ turn to bring its plane parallel to the field direction). The total charge flown in the coil (measured by a ballistic galvanometer connected to the coil) is $7.5 \; mC$. The combined resistance of the coil and the galvanometer is $0.50 \; \Omega$. Estimate the field strength of the magnet.

$A$ coil has an area $0.06 \ m^2$ and it has $600$ turns. After placing the coil in a magnetic field of strength $5 \times 10^{-5} \ Wb/m^2$,it is rotated through $90^{\circ}$ in $0.2 \ s$. The magnitude of average e.m.f induced in the coil is

$A$ bar magnet is moved along the axis of a copper ring placed far away from the magnet. Looking from the side of the magnet,an anticlockwise current is found to be induced in the ring. Which of the following may be true?

Magnetic flux linked with the coil is given by $\phi(t) = 2t^2 + 2t + 1$ and its resistance is $10 \ \Omega$. The current passing through the coil at $t = 2 \ s$ is . . . . . . $A$.

$A$ rectangular loop of length $2.5 \ m$ and width $2 \ m$ is placed at $60^{\circ}$ to a magnetic field of $4 \ T$. The loop is removed from the field in $10 \ s$. The average emf induced in the loop during this time is