The current in a coil changes steadily from $$3 \mathrm{~A}$$ to $$5 \mathrm{~A}$$ in $$0.2 \mathrm{~s}$$ when an emf of $$2 \mu \mathrm{V}$$ is induced in it. The self-inductance of the coil is

The magnetic flux linked with a coil is given by the equation: $$\phi=8 t^2+t+10$$. The e.m.f. induced in the coil in the $$3^{\text {rd }}$$ second will be

A wire ' 1 ' $$\mathrm{cm}$$ long bent into a circular loop is placed perpendicular to the magnetic field of flux density '$$B^{\prime} W b \mathrm{~m}^{-2}$$. Within $$0.1 \mathrm{sec}$$, the loop is changed into a square of side '$$a$$' $$\mathrm{cm}$$ and flux density is doubled. The value of e.m.f. induced is

In an inductor of self-inductance $$2 \mathrm{~mH}$$, current changes with time (in sec) according to the relation, $$I=(3 t^2-3 t+8) A$$. The emf becomes zero at