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

Options

A. 3.20 s
B. 2.94 s
C. 5.94 s
D. 3.10 s

Answer

B

Explanation

We have , v = 1000 Hz and lambda = `34 cm = (34)/(100)` m
The wave speed, ` v = u lambda = 100 [ (34)/( 100)] = 340 m s^(-1)`
the time taken by the wave to travel 1 km is
`t = (s)/(v) = (1 km)/( 340 m s^(-1)) = (100 m)/( 340 m s^(-1)) = 2 . 90 s `