The physical quantity which is measure in the unit of wb $$\mathrm{A}^{-1}$$ is
The current following through an inductance coil of self-inductance $$6 \mathrm{~mH}$$ at different time instants is as shown. The emf induced between $$t=20 \mathrm{~s}$$ and $$t=40 \mathrm{~s}$$ is nearly
A rod of length $$2 \mathrm{~m}$$ slides with a speed of $$5 \mathrm{~ms}^{-1}$$ on a rectangular conducting frame as shown in figure. There exists a uniform magnetic filed of $$0.04 \mathrm{~T}$$ perpendicular to the plane of the figure. If the resistance of the rod is $$3 \Omega$$. The current through the rod is
The current in a coil of inductance $$0.2 \mathrm{H}$$ changes from $$5 \mathrm{~A}$$ to $$2 \mathrm{~A}$$ in $$0.5 \mathrm{~s}$$. The magnitude of the average induced emf in the coil is