2025 · Q6
A sound wave travelling at a speed of 330 m/s produces 20 crests and 20 troughs in 0.1 second. The wavelength of the sound wave is:
General KnowledgePhysics
- A1.1 m
- B3.3 m
- C1.65 m.
- D2.2 m
Explanation
Twenty crests and twenty troughs correspond to 20 complete waves produced in 0.1 second. The frequency is therefore f = 20/0.1 = 200 Hz. Using the wave relation v = fλ, the wavelength is λ = v/f = 330/200 = 1.65 m. Option B (3.3 m) would result from counting only 10 waves, and option A (1.1 m) from miscounting the frequency.