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JAMB Physics 1994 Question 31

Question 31

Sound

A pipe of length 45cm is closed at one end. Calculate the fundamental frequency of the sound wave generated in the pipe if the velocity of sound in air is 360 m s−1. (Neglect end corrections).

  1. A.5.5 Hz
  2. B.148.5 Hz
  3. C.200.0 Hz
  4. D.550.0 Hz
Show the answer and explanation

Answer: C (200.0 Hz)

Explanation

For a closed pipe, L = λ/4, so λ = 4 × 0.45 = 1.8 m and f = 360 ÷ 1.8 = 200.0 Hz.