AMIETE – ET (NEW SCHEME) - Code: AE63
Subject: ELECTROMAGNETICS & RADIATION SYSTEMS
Time: 3 Hours
Max. Marks:
100
NOTE: There are 9 Questions in all.
· Question 1 is compulsory and
carries 20 marks. Answer to Q.1 must be written in the space provided for it in
the answer book supplied and nowhere else.
· Out of the remaining EIGHT
Questions answer any FIVE Questions. Each question carries 16 marks.
· Any required data not explicitly
given, may be suitably assumed and stated.
Q.1 Choose
the correct or the best alternative in the following: (2
10)
a. The electric field intensity 
at
any point due to point charge is given by
(A) 
(B) 
(C) 
(D) 
b. Ampere’s law in differential form is given by
(A) 
(B) 
(C) 
(D) 
c. The relationship
between electric field intensity 
and electric potential V is given by
(A) 
(B) 
(C) 
(D) 
d. A uniform plane
wave with an intensity of electric field equal to 1 volt/m is travelling in
free space. The magnitude of associated
magnetic field is
(A) 
A/m (B) 
A/m
(C) 
A/m (D) 
A/m
e. The intrinsic impedance
of free space is
(A) 73 
(B) 277
(C) 100 (D) 377
f. If 
, the charge density at the point P(1,5,9) is
(A) 79 
(B) 50
(C) 52 (D) 85
g. If two parallel
wires are separated by 10cm in air and carrying a current of 10A in the same
direction. Find the force per meter length.
(A) 
N/m (B) 
N/m
(C) 
N/m (D) 
N/m
h. The expression
for equation of continuity is
(A)
(B) 
(C) 
(D) 
i. The standard reference antenna for the
directive gain is the
(A) Infinitesimal dipole (B) Isotropic antenna
(C) Elementary doublet (D) Half wave dipole
j. Frequency in
the UHF range normally propagates by means of
(A) Ground wave (B)
Sky wave
(C) Surface wave (D)
Space wave
Answer any FIVE Questions out
of EIGHT Questions.
Each question carries 16
marks.
Q.2 a. Derive Integral and differential form of Maxwell’s
first equation as applied to the electrostatic. (8)
b. If electric
flux density 
in a region is given by:
.
Find the total charge in a
volume defined by six planes for which 
, 
, 
(8)
Q.3 a. Derive an expression for energy density in
the electrostatic field. (8)
b. The
potential field V is given by
.
Find the following at point P (-4, 3, 6)
(i) Potential V
(ii) Electric
field intensity
(iii) Direction of
(iv) Electric flux density
(v) Volume
charge density 
(8)
Q.4 a.
Derive the Poission’s
and Laplace equation in cartessian, cylindrical and spherical co-ordinates. (10)
b. Given
potential field 
(i) show
that 
(ii) find A and B so that V = 100 volts and 
at 
. (6)
Q.5 a. State and explain Maxwell’s equation in differential
and integral form for time varying field . (8)
b. The electric
and magnetic fields are given by
sin x sin t 
and
cos x cos t 
Do the fields satisfy Maxwell’s equation? (8)
Q.6 a. State
and derive the magnetic boundary conditions. (8)
b. Assume that 
in region 1 where z
> 0, while 
in region 2 wherever z < 0. Moreover 
on the surface z =
0. A field 
in region 1. Determine
the value of 
. (8)
Q.7 a. State and prove Stokes theorem. Using Stokes
theorem, obtain Ampere’s law in integral form. (8)
b. The portion of a spherical surface is
specified by r = 4,
, 
and the closed path
forming its perimeter is composed of three circular arcs. Given the magnetic
field 
sin
+ 18 r sin
cos
, evaluate 
(8)
Q.8 a. Define
the following:
(i) Critical frequency (ii) Virtual height
(iii)MUF (iv)
Skip distance (8)
b. With neat
diagram, explain resonant and non resonant antenna. (8)
Q.9 a. Explain the following terms with reference to
an antenna:
(i) Directive gain (ii) Directivity and power gain
(iii) Radiation resistance (iv) Antenna efficiency
(v) Bandwidth (vi) Beamwidth (12)
b. Calculate the
beamwidth between nulls of a 2m diameter paraboloid reflector used at 6 GHz.
Also calculate the gain of the antenna. (4)