passwella.
Menu

JAMB Physics 1997 Question 29

Question 29

Sound

Under constant tension and constant mass per unit length, the note produced by a plucked string is 500 Hz when the length of the string is 0.90 m. At what length is the frequency 150 Hz?

  1. A.3 m
  2. B.4 m
  3. C.5 m
  4. D.6 m
Show the answer and explanation

Answer: A (3 m)

Explanation

Frequency is inversely proportional to length: f1L1 = f2L2. 500 × 0.90 = 150 × L, so L = 3 m.