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JAMB Physics 1989 Question 22

Question 22

Sound

In a sound wave in air, the adjacent rarefactions and compressions are separated by a distance of 17 cm. If the velocity of the sound wave is 340 m s−1 determine the frequency.

  1. A.10 Hz
  2. B.20 Hz
  3. C.1000 Hz
  4. D.5780 Hz
Show the answer and explanation

Answer: C (1000 Hz)

Explanation

A compression and the next rarefaction are half a wavelength apart, so λ = 34 cm. f = v/λ = 340/0.34 = 1000 Hz.