1. Prove that the electric field strength at any point outside a spherical charge distribution is the same as though the whole charge were concentrated at the centre.

2. What do you mean by the capacitance of a capacitor On what factors does it depend Show that the energy density of electric field in the region between the plates of a parallel plate capacitor is given by

u 1/2 € E^2

3. Define the Green's' function with reference to electrostatic potential problems. Prove that this function satisfies the symmetry

G x).

4. A long horizontal rigidly supported wire carries a current ia of 100 A. Directly above it and parallel to it is a fine wire that carries a current ib of 20 A and weighs 0·03 N/m. How far above the lower wire should the second wire be kept, if we wish to support it by magnetic repulsion? Given permeability constant
Il= 41t x 10-7 Wb/m.


5. Establish Maxwell's equations for the electromagnetic fields and obtain an expression for Poynting vector.

6. Explain the theory of propagation of electromagnetic waves in a conducting medium and also explain why in high frequency circuits current flows only on surface of conductors.

7. Give briefly the general methods for the solution of potential problems in electrostatics and compare their merits and limitations.

8. A charge 1 micro C is placed at the centre of a hollow cube. Calculate the electric flux diverging

through the centre.

through each face.

9. The rails of a railway track are 1.5 m apart and assumed to be insulated from one another. Calculate the emf in volts that exists between the rails, if a train is passing at 100 km/hour:. Assume that the horizontal component of Earth's magnetic field is 0·36 oersted and tan e =1.036, where e is the angle of dip.

10. Write short notes on any two of the following:

Snell's Law of Refraction

Transmission Line Parameters

Generalized form of Gauss's Theorem