Self Assessment Quiz

1. A coaxial cable consists of an inner conductor of radius a and an outer conductor of radius b. The current in the inner conductor is uniformly distributed while the outer conductor has negligible thickness and provides a return path to the current. Calculate the self inductance of the cable.

2. Find the mutual inductance of two coplanar squares with a common centre  assuming that the square located inside is much smaller in dimension b than the bigger square which has a side a.

3. The current through a straight wire varies with time as  where the current is in Amperes and time in seconds. If the radius of cross section of the wire is 50 (mm)2 and the resistivity  , estimate the displacement current density and compare it with the conduction current density.

4. A capacitor plate of area 0.3 m2 is being charged at a uniform rate so that the electric field inside the plate varies with time as  V/m-s. Calculate the displacement current and estimate the magnetic field strength at a distance 5 cm from the centre of the capacitor plate along a line parallel to both the plates.