Electromagnetic Waves

8 Questions
  1. 1
    Which of the following statements with regard to stealth technology is/are correct?
    1. Stealth objects have a very small radar cross-section and are coated with Radar Absorbing Material.
    2. Stealth objects can be detected using specific frequencies.
    3. Stealth objects are coated with metamaterials to increase the scattering of electromagnetic radiation.
    Select the answer using the code given below:
    UPSC CSE I - 2026
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    Answer: C. 1 and 2 only

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  2. 2
    Consider the following activities :
    1. Identification of narcotics on passengers at airports or in aircraft
    2. Monitoring of precipitation
    3. Tracking the migration of animals
    In how many of the above activities can the radars be used ?
    UPSC CSE I - 2024
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    Answer: B. Only two

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  3. 3

    Assertion (A): Radio waves bend in a magnetic field.

    Reason (R): Radio waves are electromagnetic in nature.

    Codes:

    UPSC CSE I - 2008
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    Answer: D. A is false but R is true

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  4. 4

    Which of the following types is used by computed tomography employed for visualisation of the internal structure of human body?

    UPSC CSE I - 2007
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    Answer: A. X-ray

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  5. 5

    Which one of the following types of glass can cut off ultraviolet rays?

    UPSC CSE I - 2007
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    Answer: D. Crookes glass

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  6. 6

    Consider the following statements:

    1. Light of longer wavelength are scattered much more than the light of shorter wavelength.
    2. The speed of visible light in water is 0.95 times the speed in vacuum.
    3. Radio waves are produced by rapidly oscillating electrical currents.
    4. To detect the over speeding vehicles, police use the Doppler effect of reflected short radio waves.

    Which of these statements are correct?

    UPSC CSE I - 2002
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    Answer: D. 3 and 4

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  7. 7

    Which one of the following does a TV remote control unit use to operate a TV set?

    UPSC CSE I - 2000
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    Answer: A. Light waves

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  8. 8

    Barium in a suitable form is administered to patients before an X-ray examination of the stomach; because

    UPSC CSE I - 1999
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    Answer: C. barium is a good absorber of X-rays and this helps the stomach to appear clearly in contrast with the other regions in the picture.

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