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ECE :: Electromagnetic Field Thoery

  1. If the electric field intensity is given by , the potential difference between x(2, 0, 0) and y(1, 2, 3) is

  2. A.
    +1 volt
    B.
    -1 volt
    C.
    +5 volt
    D.
    +6 volt

  3. Medium 1 has the electrical permittivity ε1 = 1.5 ε0 farad/m and occupies the region to the left of x = 0 plane. Medium 2 has the electrical permittivity ε2 = 2.5 ε0 farad/m and the occupies the region to the right of x = 0 plane. If E1 in medium 1 is volt/m, then E2 in medium 2 is


  4. Polarization of a wave is

  5. A.
    direction of electric field
    B.
    direction of magnetic field at some fixed point in space
    C.
    either (a) or (b)
    D.
    none of the above

  6. Calculate the critical frequency for the E layer if maximum ionic densities are 3 x 106

  7. A.
    15.58 x 106
    B.
    15.58 kHz
    C.
    1.58 x 103
    D.
    None of the above

  8. Calculate the directivity of a given linear end fire, uniform array of 20 element, each separated by λ/3

  9. A.
    100
    B.
    10
    C.
    26.66
    D.
    30

  10. For a 400 kHz transmission line having L = 0.5 mH/km, C = 0.08 mF and negligible R and G, the velocity propagation will be

  11. A.
    15.8303 km/s
    B.
    15.830 km/s
    C.
    1.583 km/s
    D.
    0.1583 km/s

  12. Antenna efficiency of antenna is, if radiation resistance is 370 Ω and loss resistance is 100 Ω

  13. A.
    80%
    B.
    87%
    C.
    78%
    D.
    21.27%

  14. At a particular time it is observed that the frequencies of F layer at Delhi is 3 MHz the maximum electron density is

  15. A.
    11 x 1010
    B.
    1.1 x 1010
    C.
    0.11 x 1010
    D.
    11 x 1012

  16. The effective length of an λ/2 antenna (Given Rr = 73 Ω and (Ae)max = 0.13 λ2 and η = 120 p is __________ .

  17. A.
    0.6348 λ
    B.
    0.317 λ
    C.
    0.158 λ
    D.
    0.371 λ

  18. Calculate cut off frequency for dominant mode in rectangular waveguide if dimensions are a = 2, b = 1 cm.

  19. A.
    7.5 GHz
    B.
    1.5 GHz
    C.
    15 GHz
    D.
    150 GHz