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JAMB Physics 1982 Question 47

Question 47

Sound

In a resonance tube experiment (Fig. 12) the frequency of the tuning fork is 750 Hz and the resonating length of the air column is 0.3 m as shown. The velocity of the wave is

Diagram for this question
  1. A.1,850 m s−1
  2. B.225 m s−1
  3. C.300 m s−1
  4. D.53 × 10−5 m s−1
  5. E.2,500 m s−1
Show the answer and explanation

Answer: C (300 m s−1)

Explanation

The diagram shows three-quarters of a wavelength in the 0.3 m column, so λ = 0.4 m and v = fλ = 750 × 0.4 = 300 m s−1.