SRM University 2007 B.Tech Electronics and Communications Engineering Bank : Electromagnetic Field Theory - Question Paper

11. a) obtain the divergence of A at P(5,?/2,1) where A = rz sin? ar + 3rz2 cos? a?
b) compute divergence at P(1,?/6,5/3) where f= 2r cos? ar+ r1/2 a?.
12. Given the potential v= 10/r2 sin?.cos?
a) obtain electric flux density d at (2,?/2,0)
b) compute the work done in moving a 10 ?C charge from point A(1,30o,120o) to b(4,90o,60o).

UNIT – II - Conductors, Dielectrics and Capacitance
Part – A
1. Write the boundary conditions on the surface ranging from 2 dielectric media of various relative permittivity.
2. Give the difference ranging from conductors and dielectrics.
3. Define displacement current.
4. Define polarization.
5. What is meant by polar dielectrics?
6. Write down the formula of continuity in point form.
7. Give the point form of Ohm’s legal regulations defining every notation.
8. What is the relation ranging from displacement current and conduction current?
9. State the boundary conditions on D and E ranging from 2 dielectric surfaces.
10. Write the expression for the energy stored in a capacitor in terms of charge and capacitance.
11. Write the formula to obtain the capacitance of an isolated sphere. discuss the terms.
12. Obtain the expression for the capacitance of 2 parallel plates.
13. State continuity formula.
14. State continuity formula in integral and differential forms.
15. Define method of images.
16. Write the boundary conditions on the interface of a conductor and a dielectric.
17. provide the general form of Poisson’s formula.
18. Give the general form of Laplace formula.
19. Differentiate conductors and dielectrics.
20. What is break down potential?
21. Give the expression for capacitance ranging from 2 parallel conducting wires.
22. Define dielectric strength of a material.
23. Write the expression for the capacitance of coaxial cables.
24. Under stable conditions, tangential component of electric field is zero. Justify.

Part – B

1. Discuss the properties and boundary conditions of dielectric materials.
2. Give and derive the expression for capacitance of coaxial cables with single and 2 dielectrics.
3. Write down the uniqueness theorem and discuss. (6)
4. Derive the expression for capacitance of a two-wire line.
5. Write the expression for Laplace and Poisson’s formula and derive it for different coordinate systems.
6. Deduce an expression for the joint capacitance of 2 capacitors, C1 and C2, (i) in series and (ii) in parallel. If C1 = 100 microfarad and C2 = 50 microfarad, compute a) the joint capacitance and b) the total energy stored with a steady applied potential difference of 1000V.

Earning:   Approval pending.