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JAMB Physics 2001 Question 17

Question 17

Waves

A plane sound wave of frequency 85.5 Hz and velocity 342 m s−1 is reflected from a vertical wall. At what distance from the wall does the wave have an antinode?

  1. A.2 m
  2. B.4 m
  3. C.1 m
  4. D.3 m
Show the answer and explanation

Answer: C (1 m)

Explanation

λ = v/f = 342/85.5 = 4 m. There is a node at the wall, and the first antinode is λ/4 = 1 m from it.