Waves

Waves

Moderate Questions
Difficult Questions

Physics of Sound

Oscillations
Waves
  1. Which of the following equations represent a wave?








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    y = A sin (at – bx + c) represents a wave, where a may correspond to ω and b may correspond to K.

    Correct Option: C

    y = A sin (at – bx + c) represents a wave, where a may correspond to ω and b may correspond to K.

  1. A wave of frequency 100 Hz is sent along a string towards a fixed end. When this wave travels back after reflection, a node is formed at a distance of 10 cm from the fixed end of the string. The speeds of incident (and reflected) waves are








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    As fixed end is a node, therefore, distance between two consecutive nodes

    -
    λ
    		 - 10 cm.
    2

    λ = 20 cm = 0.2 m
    As v - nλ ∴ v = 100 × 0.2 = 20 m/s

    Correct Option: C

    As fixed end is a node, therefore, distance between two consecutive nodes

    -
    λ
    		 - 10 cm.
    2

    λ = 20 cm = 0.2 m
    As v - nλ ∴ v = 100 × 0.2 = 20 m/s

  1. The temperature at which the speed of sound becomes double as was at 27°C is








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    We have c ∝ √T

    ∴
    c1
    		 = √
    T1
    c2T2

    ⇒
    c1
    		 = √
    (27 + 273)k
    2c2T2

    ⇒ T2 = 1200k = 927°C

    Correct Option: C

    We have c ∝ √T

    ∴
    c1
    		 = √
    T1
    c2T2

    ⇒
    c1
    		 = √
    (27 + 273)k
    2c2T2

    ⇒ T2 = 1200k = 927°C

  1. With the propagation of a longitudinal wave through a material medium, the quantities  transmitted in the propagation direction are








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    With the propagation of a longitudinal wave, energy alone is propagated.

    Correct Option: B

    With the propagation of a longitudinal wave, energy alone is propagated.

  1. An air column, closed at one end and open at the other, resonates with a tuning fork when the smallest length of the column is 50 cm. The next larger length of the column resonating with the same tuning fork is :








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    For a closed organ pipe first minimum resonating length
    L1 = λ/4 = 50 cm
    ∴ Next or second resonating length, L2
    = 3λ/4 = 150 cm.

    Correct Option: C

    For a closed organ pipe first minimum resonating length
    L1 = λ/4 = 50 cm
    ∴ Next or second resonating length, L2
    = 3λ/4 = 150 cm.