# RGPV Previous Year Question Papers 4th Sem

# Electromagnetic Theory Dec 2004

** **

**Note:Attempt any five questions.**

**All question carry equal marks.**

** Assume suitable data wherever**

necessary.

1 (a) State gauss law and prove that V.D= pv.

(b) (i) Transform a vector A= ya_{x} –x.a_{y}+z.a_{z }into cylindrical coordinates .

(ii) Obtain electric field in all regions due to following charge distribution in free space :

P(rФz) =0,0<r<a

= p0, a<r<b

= 0, b<r<

2 (a) Drive the relation for energy stored in electro –static field .

(b) State and prove stake’s theorem.

3 (a) Explain electronic polarization and drive the equation D= E+P.

(b) Prove Poisson’s and Laplace equation starting from point from of Gauss law .

4 (a) State and prove ampere’s circuital law. What is the application of this law?

(b) A rectangular current loop in the z =0 plan has corners at (0,0,0) ,(1,0,0), (1,2,0) and (0,2,0). The

loop carries a current of 5 Amp in a_{x} direction . Find the total force and torque on the loop

produced by the magnetic fild B= (2a_{x}+ 2a_{y} -4a_{z}) eb/m^{2 }.

5 (a) State and prove magnetic boundary conditions .

(b) Using the concept of vector magnetic potential , find the magnetic flux density at a point due to a

long straight filamentary conductor carrying a current I in a_{z} direction .

6 (a) Drive the expression for self inductance of solenoid .

(b) Drive the Maxwell equation V×E= – B t and express all the Maxwell’s equation in integral from .

7 (a) Determine the relation between E and H in a uniform plane wave .

(b) A distortion less line has characteristic impedance of 60 ,Attenuation constant α =20 m Np/m,

wave velocity is 3/5 times that of light . Find parameters of transmission line the and wavelength

at frequency of 100 MHz .

8 Write short note of any two of the following :

(i) Pointing vector (ii) Ohm’s Law in point from (iii) Polarisation of waves