CS/B.
TECH(N)/ODD/SEM-5/5587/2024-2025
MAULANA ABUL KALAM AZAD UNIVERSITY OF TECHNOLOGY, WEST BENGAL
Paper Code : EC501 Electromagnetic Waves
Time Allotted : 3 Hours Full Marks :70
The Figures in the margin indicate full marks.
Candidate are required to give their answers in their own words as far as practicable
Group-A (Very Short Answer Type Question)
1. Answer any ten of the following : [ 1 x 10 = 10 ]
(I) What is the difference between a scalar and a vector quantity?
(II) What is the value of intrinsic impedance of free space?
(III) In a TEM wave how the E field and the H field are oriented with respect to the direction of propagation?
(IV) What is the skin depth of a perfect conductor?
(V) What is the length of a half wave dipole antenna for operating frequency of 10MHz?
(VI) If A And B are vector quantities , A.B=?
(VII) Electric field inside a conducting sphere is always ----- .
(VIII) Does phase velocity depend on frequency in a lossless line?
(IX) Whether TEM mode of propagation is possible in a rectangular waveguide?
(X) What are the primary parameters of a transmission line?
(XI) What is Laplacian of a scalar quantity 'V' in rectangular cartesian coordinate?
(XII) What is Poynting vector?
Group-B (Short Answer Type Question)
Answer any three of the following [ 5 x 3 = 15 ]
2. Obtain an expression for average power in a loss less transmission line. [5]
3. What is meant by cut-off frequency of a rectangular wave guide? What are TE and TM mode of propagation? [5]
4. What is a dipole antenna ? [5]
What is the length of a half wave dipole antenna operating at 1GHz?
5. A (100+j150 ) ohm load is connected to a transmission line of 50ohm characteristic impedance . What will be the [5]
values of load reflection coefficient and VSWR?
6. In a rectangular waveguide for which a = 2b, the cut-off frequency for TE02 mode is [5]
12 GHz. What is the cut-off frequency for TM11 mode ?
What is meant by evanescent mode?
Group-C (Long Answer Type Question)
Answer any three of the following [ 15 x 3 = 45 ]
7. (a) Write down Maxwell's equation for time varying electromagnetic fields , when the medium is homogeneous [5]
, source free, lossless , isotropic and linear.
(b) Obtain wave equation for a conducting medium. [6]
(c) What is meant by perfect conductor? [4]
Explain the concept of skin depth.
8. Show how Maxwell's equations can be obtained from different laws of electromagnetics. [ 15 ]
9. (a) Which of the following media may be treated as conducting at 8 MHz? [8]
(a) Wet marshy soil (ε= 15εo,µ = µo, σ = 10-2 S/m)
(b) Sea water (ε = 81εo , µ = µo , σ = 25 S/m)
(b) A uniform plane wave in a lossy medium has a phase constant of 1.6 rad/m at 107 Hz and [7]
its magnitude is reduced by 60% for every 2 m travelled. Find the skin depth and speed of
the wave.
10. (a) Obtain transmission line equations. Find out the solutions of these equations. [8]
1/2
(b) What are propagation constant and characteristic impedance of the line? Obtain formulas for these [7]
quantities.
11. (a) Define radiation intensity, directivity and efficiency of an antenna . [ 10 ]
(b) Differentiate between dipole and monopole antennas. [5]
*** END OF PAPER ***
2/2
