Question

A sound source sends waves of 400 Hz. It produces waves of wavelength 2.5 m. The velocity of sound waves is:

• A. 100 m/s
• B. 1000 m/s
• C. 10000 m/s
• D. 3000 m/s

Answer 1

The correct option is B

1000 m/s

Frequency is the number of times a wave oscillates in 1 second and wavelength is the distance between two consecutive compressions or rarefactions. So in the one-second wave has travelled, d = frequency $\times$ wavelength.
So, $v=400\times 2.5\frac{m}{s}$
$v=1000\frac{m}{s}$