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Civil Engineering :: Elements of Remote Sensing

  1. Electromagnetic spectrum contains:

  2. A.

     Gamma rays (wave length < 10⁻¹⁰ m)

    B.

     Ultraviolet rays (wave length < 10⁻⁶ m)

    C.

     Infrared rays (wave length < 10⁻⁴ m)

    D.

     All of these

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  3. Earth observations from a satellite platform provide:

  4. A.

     Synoptic view of a large area

    B.

     Constant solar zenith angles and similar illumination conditions

    C.

     Repetitive observations of the same area with intervals of a few minutes to a few weeks

    D.

     All of these

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  5. The instruments which provide electromagnetic radiation of specified wave length or a band of wave lengths to illuminate the earth surface are called:

  6. A.

     Sensors

    B.

     Passive sensors

    C.

     Active sensors

    D.

     None of these

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  7. Pick up the correct statement from the following

  8. A.

     The ratio of the up flux and down flux just above the snow surface, is called albedo

    B.

     Spectral albedo of snow is calculated for the semi-infinite snow thickness

    C.

     Water equivalent height of snow is the height of water column obtained by melting snow

    D.

     All of these

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  9. Consider the following statements regarding the satellite imaging:
    1. The satellite orbit is fixed in the inertial space
    2. During successive across-track imaging, the earth rotates beneath the sensor
    3. The satellite images a skewed area
    Which one of the following statements is/are correct?

  10. A.

     1, 2, 3

    B.

     1, 3

    C.

     2, 3

    D.

     1, 2

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  11. Due to scan geometry of a satellite sensor:

  12. A.

     The off-nadir resolution is degraded

    B.

     The ground distance swept by the senor, IFOV is proportional to sec2θ, where θ is the angle of scan measured from the nadir

    C.

     The details towards the edge of the scan get compressed

    D.

     All of these

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  13. Coherence of two electromagnetic waves takes place if their phase difference is:

  14. A.

     Constant in time

    B.

     Constant in space

    C.

     Constant in time and space

    D.

     None of these

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  15. The basic requirement of any sensor system is:

  16. A.

     Radiometric resolution

    B.

     Spatial resolution

    C.

     Spectral resolution

    D.

     All of these

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  17. A passive sensor uses:

  18. A.

     Sun as the source of energy

    B.

     Flash light as a source of energy

    C.

     Its own source of energy

    D.

     None of these

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  19. DGPS is based on the concept that bias errors in the position of locations in a given local area, are same if their distances are within

  20. A.

     25 km

    B.

     50 km

    C.

     75 km

    D.

     100 km

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