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ECE :: Electromagnetic Field Thoery

Electromagnetic Field Thoery - Section 1
Electromagnetic Field Thoery - Section 2
Electromagnetic Field Thoery - Section 3
Electromagnetic Field Thoery - Section 4
Electromagnetic Field Thoery - Section 5
Electromagnetic Field Thoery - Section 6
Electromagnetic Field Thoery - Section 7
Electromagnetic Field Thoery - Section 8
Electromagnetic Field Thoery - Section 9
Electromagnetic Field Thoery - Section 10
Electromagnetic Field Thoery - Section 11
Electromagnetic Field Thoery - Section 12
Electromagnetic Field Thoery - Section 13
Electromagnetic Field Thoery - section-14
Electromagnetic Field Thoery - section-15

  1. The effective height of a vertical radiator can be increased by

    2. A.
    loading with lumped inductance
    B.
    supporting on an insulator
    C.
    capacitive loading
    D.
    giving input more power

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  2. When an electromagnetic wave travelling in one medium strikes upon a second medium (having a different conductivity) the wave will be

    3. A.
    totally transmitted
    B.
    totally reflected
    C.
    neither transmitted nor reflected
    D.
    partially transmitted and partially reflected

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  3. For transmission of waveform a dielectric medium of permittivity ε1 into a dielectric medium of lower permittivity ε2 , (ε1 > ε2) the critical angle of incidence θc (relative to the interface) is given by

    4. A.
    sin-1
    B.
    cos-1
    C.
    tan-1
    D.

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  4. The line of sight communication requires that transmit and receive antennas to face each other. If the transmit antenna is vertically polarized, for the best reception the receive antenna should be

    5. A.
    horizontally polarized
    B.
    vertically polarized
    C.
    at 45° with respect to horizontal polarization
    D.
    at 45° with respect to vertical polarization

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  5. An antenna has 40 Ω resistance and 60 Ω radiation resistance. The efficiency of the antenna is

    6. A.
    30%
    B.
    40%
    C.
    50%
    D.
    60%

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  6. The duration of sunspot cycle is

    7. A.
    1 year
    B.
    11 years
    C.
    55 years
    D.
    100 years

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  7. Electromagnetic cavity resonators (energy storage devices) are used in

    8. A.
    wave meters
    B.
    bandpass filters
    C.
    high frequency tubes
    D.
    all of the above

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  8. Waveguides are generally used above

    9. A.
    20 MHz
    B.
    100 MHz
    C.
    200 MHz
    D.
    1000 MHz

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  9. Maximum power transfer will take place in a practical antenna if (XL = Load Reactance, XA Antenna Reactance)

    10. A.
    XL = - XA
    B.
    XL = XA
    C.
    XL = XA
    D.
    XL = XA2

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  10. Which type of fading causes serious distortion of modulated signal?

    11. A.
    Selective fading
    B.
    Interference fading
    C.
    Absorption fading
    D.
    Polarization fading

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