Anna University Chennai 2005 B.E ELECTROMAGNETICS AND RADIATION - Question Paper

Code: A - 14 Subject: ELECTROMAGNETICS AND RADIATION
Time: three Hours Max. Marks: 100
NOTE: There are 11 ques. in all.
ques. one is compulsory and carries 16 marks. ans to Q. 1. must be written in the space given for it in the ans book supplied and nowhere else.
ans any 3 ques. every from Part I and Part II. every of these ques. carries 14 marks.
Any needed data not explicitly given, may be suitably presumed and said
Q.1 Choose the accurate or best option in the following: (2x8)
a. A ball having charge 'q' floats in mid air, in presence of a line charge having linear charge density . If the distance of the ball from the charge is 'd' then the mass of the ball is

(A) (B)
(C) (D)
b. A positive charged pendulum is oscillating in a uniform electric field (Fig.1).
Its time period as compared to that when it was uncharged :

(A) will increase.
(B) will reduce.
(C) will not change.
(D) will 1st increase and then reduce.

c. The equivalent capacitance ranging from A and B (Fig.2) is
(A) two C. (B) three C.
(C) four C. (D) .
d. An electron moves straight inside a charged parallel plate capacitor of uniform surface charge density (Fig.3). The space ranging from the plates is filled with constant magnetic field of induction . Neglect gravity, the time of straight line motion of the electron in the capacitor is
(A) (B)
(C) (D)
1
Index Next>>e. In a 2 region system, a plane wave is arriving at normal incidence in air with amplitude and frequency The slab is teflon . The amplitude of the reflected wave is:
(A) 18.34 v/m. (B) -18.34 v/m.
(C) 36.68 v/m. (D) -36.68 v/m.

f. The lower cut-off frequency of a rectangular waveguide with inside dimensions operating at nine GHz is
(A) 3.8 GHz. (B) nine GHz.
(C) 7.6 GHz. (D) None of the above.

g. The radiation resistance of a dipole having length four cm, radiating 50 W of power at a frequency of 500 MHz is
(A) 3.5 . (B) 0.82 approx.
(C) 1.75 . (D) seven .

h. The MUF of transmission ranging from 2 stations 500 Km apart at and minimum value of incident angle is
(A) 0.7 MHz. (B) 25.4 MHz.
(C) 12.7 MHz. (D) 18 MHz.
PART I
ans any 3 ques.. every ques. carries 14 marks.

Earning:   Approval pending.