Sound

7 Questions
  1. 1

    Assertion (A): A jet aircraft moving at Mach Number equal to 1 travels faster at an altitude of 15 km than while moving at Mach Number equal to 1 near the sea level.

    Reason (R): The velocity of sound depends on the temperature of the surrounding medium.

    Codes:

    UPSC CSE I - 2007
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    Answer: D. A is false but R is true

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  2. 2

    Consider the following statements:

    1. A flute of smaller length produces waves of lower frequency.
    2. Sound travels in rocks in the form of longitudinal elastic waves only

    Which of the statements given above il/are correct?

    UPSC CSE I - 2007
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    Answer: D. Neither 1 nor 2

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  3. 3

    In which one among the following is the speed of sound maximum?

    UPSC CSE I - 2006
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    Answer: D. Wood

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  4. 4

    What does the term Dolby B or Dolby C printed on tape- recorders and other sound systems refer to:

    UPSC CSE I - 2006
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    Answer: C. noise Reduction Circuit

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  5. 5

    Which one of the following statements is not correct?

    UPSC CSE I - 2003
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    Answer: C. The velocity of sound in air decreases as the humidity increases

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  6. 6

    For reproducing sound, a CD (Compact Disc) audio player uses a

    UPSC CSE I - 2000
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    Answer: C. laser beam

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  7. 7

    A noise level of 100 decibels would correspond to

    UPSC CSE I - 2000
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    Answer: D. noise from a machine shop

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