A coil of resistance $16 \Omega$ is placed with its plane perpendicular to a uniform magnetic field whose flux ( $\phi$ in $10^{-3}$ weber) changes with time ( $t$ in second) as $\phi=5 t^2+4 t+2$. The induced current at time $t=6$ second is

The small energy losses in transformers due to eddy currents can be reduced by

The radius of a coil of $N$ turns is $R$. If the plane of the coil is placed parallel to a uniform magnetic field $B$, then the flux linked with the coil is

An emf of 2.8 mV is induced in a rectangular loop of area $150 \mathrm{~cm}^2$ when the current in the loop changes from 3 A to 8 A in a time of 0.2 s . Then, the self-inductance of the loop is