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JAMB Physics 1989 Question 19

Question 19

Waves

A vibrator of frequency 60 Hz is used in generating transverse stationary waves in a long thin wire. If the average distance between successive nodes on the wire is 45 cm, find the speed of the transverse waves in the wire.

  1. A.27 m s−1
  2. B.54 m s−1
  3. C.90 m s−1
  4. D.108 m s−1
Show the answer and explanation

Answer: B (54 m s−1)

Explanation

Successive nodes are half a wavelength apart, so λ = 90 cm = 0.9 m. v = fλ = 60 × 0.9 = 54 m s−1.