Priyadarshini Bhagwati College of Engineering, Nagpur
(Session 2023-24)
Department of Electronics & Communication Engineering
Semester : V
CAT - 2
Subject : Electromagnetic Waves Subject Code : BEETC-502T
Duration : 1.5 Hrs Max. Marks : 35
Note :
1. All questions are compulsory. Solve questions 1 or 2, 3 or 4 and 5 or 6.
2. All questions carry marks as indicated.
3. Illustrate your answers with neat flow sheets
Q. No. Questions Marks CO BL
1 (A) (i) The power in electromagnetic waves is given by - 1 3 1
(a) Coulomb’s Law (b) Divergence Theorem
(c)Poynting’s Theorem (d) Gauss Law
(ii) For good conducting medium is 1 3 1
!
(a) 1 (b) 1 (c) 0 (d) 1
(B) State and Prove Poynting’s Theorem. 5 3 1,3
2 (A) (i) For a perfect dielectric medium, the conductivity value is - 1 3 1
(a) 0 (b) 1 (c) Less (d) More
(ii) The electromagnetic waves gets ............. from conducting 1 3 1
medium.
(a) absorbed (b) Reflected (c) Refracted (d) None
(B) Prove that the intrinsic impedance of a medium is given by - 5 3 3
s
j!
= + j!
3 (A) (i)Which of the following mode does not propagate in rectangular 1 4 1
waveguide?
(a) TE (b) TM (c) TEM (d) All TE, TM and TEM
(ii) Which of the following mode is dominant mode in rectangular 1 4 1
waveguide?
(a) T E10 (b) T E11 (c) T E01 (d) T E12
(B) Explain how rectangular waveguide acts as high-pass filter. Also 5 4 2,3
derive an expression for cut-off frequency.
(C) What will be the cut-off wavelength for dominant mode in rect- 7 4 3
angular waveguide whose breadth is 10 cm. For 2.5 GHz signal,
calculate guide wavelength, group and phase velocity, cut-off fre-
quency and characteristic impedance.
4 (A) (i) The phase velocity of wave is ........... velocity of light. 1 4 1
(a) Greater than (b) Less than (c) Equal to (d) Zero
(ii) The rectangular waveguide acts as ........... filter. 1 4 1
(a) High Pass (b) Low Pass (c) Band Pass (d) Band Reject
(B) What transmission modes are possible at operating frequency of 5 4 3
3 GHz in a rectangular waveguide with inner dimension 7 cm
3 cm. Assume air as dielectric.
(C) Prove that the geometric mean of phase velocity and group veloc- 7 4 3
ity is always equal to velocity of light.
5 (A) (i) The omnidirectional antenna radiates in ........... direction. 1 5 1
(a) One (b) Two (c) All (d) None of the above
(ii) Antenna is a transducer which converts one form of energy 1 5 1
into other form.
(a) True (b) False
(B) An antenna has a radiation resistance of 72 and a loss resistance 5 5 3
of 8 and a power gain of 12 dB. Determine antenna efficiency
and its directivity.
(C) Explain the following terms : 7 5 2
(a) Power Gain (b) Directive Gain (iii) Directivity (iv) Radiation
Intensity
6 (A) (i) The ratio of radiation intensity in a given direction from an- 1 5 1
tenna to the radiation intensity over all directions is called as ........
(a) Directivity (b) Radiation Power density
(c) Gain (d) Array factor
(ii) The axis of back lobe makes an angle of 180o with respect to 1 5 1
the beam of an antenna.
(a) True (b) False
(B) Calculate radiation resistance of a broadcast antenna which is 30 5 5 3
m high, base fed vertical conductor over a perfectly conducting
ground at a frequency of 500 kHz.
(C) Define the following terms : 7 5 1
(a) Front-Back Ratio (b) Beamwidth (c) Radiation Resistance (d)
Antenna Efficiency
