# JNTU II B.Tech I Semester Regular Examinations, November 2008

JNTU II B.Tech I Semester Regular Examinations, November 2008

ELECTROMAGNETIC WAVES AND TRANSMISSION LINES

(Electronics & Instrumentation Engineering)

SET-2

1. (a) Define potential gradient and list out salient features of potential difference.

(b) An electric dipole, 1.0ay nC-m is located at (0, 0, 0). Find out the potential

at ????1, _

4 , _

2 _.

2. (a) State and explain Ampere’s force law.

(b) If the vector magnetic potential, A = 2.0 a_ +5.0 a_ in spherical coordinates,

find B at (2.0, ?/6, 0).

3. (a) Write Maxwell’s equations for static fields and explain.

(b) In free space, D = 5.0 sin (?t + ?z) ax. Find B using Maxwell’s equations.

4. The phasor magnetic field intensity for a 400 MHz uniform plane wave propagating

in a certain lossless material is (ay ? j 5 az) e?j25x, A/m, if Em = 1000 V/m, find:

(a) ?

(b) ?

(c) ?.

5. What is Transmission Coefficient? Derive the expression for transmission coefficient of a uniform plane wave at normal incidence.

6. What are the field components for TE waves? Derive them and draw the sketches for JE10 mode.?

7. (a) What are primary constants? Explain the features of primary constants?

(b) Find the characteristic impedance of a line at 1600Hz if the following mea-

surements have been made on the line at 1600Hz, ZOC = 650 and ZSC =550.

8. Write a detailed note on a double stub matching on a line using smith chart?