Question

A sound wave has a frequency of 1000 Hz and a wavelength of 34 cm. How long will it take to travel 1 km?

• A. 6.20 s
• B. 2.94 s
• C. 5.94 s
• D. 7.10 s

Answer 1

The correct option is B

2.94 s

We have, f = 1000 Hz and
$\lambda =34cm=\frac{34}{100}m$
The wave speed is
$v=f\lambda =\left(1000s^{-1}\right)\left[\frac{34}{100}m\right]=340m/s$
The time taken by the wave to travel 1 km is:
$t=\frac{s}{v}=\frac{1km}{340m/s}=\frac{1000m}{340m/s}=2.94s$