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Electromagnetic Field Theory problems

1. The displacement flux density at a point on the surface of a perfect conductor is = 2(a_x - 3 a_z)c/m² pointing away from the surface. The charge density at that point c/m² will be
Options
A. 2
B. - 2
C. 4
D. - 4

2. The velocity of electromagnetic wave in a good conductor is
Options
A. 3 x 10⁸ m/s
B. more than 3 x 10⁸ m/s
C. very low
D. high

3. Which one of the following does represents the electric field lines for the TE₀₂ mode in the cross section of a hollow rectangular metallic waveguide?
Options
A.
B.
C.
D.

4. A parallel polarized wave is incident from air into paraffin having relative permittivity 3, the value of its Brewster angle is
Options
A. 0�
B. 30�
C. 45�
D. 60�

5. For a 400 kHz transmission line having L = 0.5 mH/km, C = 0.08 mF and negligible R and G, the value of propagation constant P will be
Options
A. 15.9 radians/km
B. 31.8 radians/km
C. 63.6 radians/km
D. 105.4 radians/km

6. The Depth of penetration of EM wave in medium having conductivity ? at a frequency of 1 MHz is 25 cm. The depth of penetration at a frequency of 4 MHz will be
Options
A. 6.25 cm
B. 12.50 cm
C. 50 cm
D. 100 cm

7. Radiation intensity of a dipole depends strongly on frequency. If at a frequency f, the intensity of radiation is 'I'. Then at a frequency of f/2, the intensity will be
Options
A.
B.
C.
D.

8. The divergence of the electric field intensity at any point equals
Options
A. 1/4 p?₀ times the volume charge density
B. l/?₀ times the volume charge density at that point
C. ?₀ times the volume charge density at that point
D. the volume charge density at that point

9. A broadside array operating at 100 cm wavelength consist of 4 half-wave dipoles spaced 50 cm apart. Each element carries radio frequency current in the same phase and of magnitude 0.5 A. The radiated power will be
Options
A. 196 W
B. 73 W
C. 36.5 W
D. 18.25 W

10. A rectangular metal waveguide filled with a dielectric of relative permittivity ?_r = 4, has the inside dimensions 3 x 1.2 cm, the cut off frequency for the dominant mode is
Options
A. 2.5 GHz
B. 5 GHz
C. 10 GHz
D. 12.5 GHz

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