Question

Find the minimum and maximum wavelengths of sound in water that is in the audible range for an average human ear. Speed of sound in water is 1450 m/s.

Answer 1

We have ,

Ultrasonic frequency =20,000 Hz ,

and Infrasonic frequency =20 Hz ,

below 20Hz and above 20,000Hz we are not able to hear any sound therefore audible frequency is in between them , from 20Hz to 20000Hz , which can be heard by human ear .

Now in water , given velocity of sound $v=1450m/s$ ,

by using the relation , $\lambda =v/f$ ,

where $f=$ frequency of sound ,

$\lambda =$ wavelength of sound ,

for $f_{in}=20Hz$ ,

${\lambda }_{max}=1450/20=72.5m$ ,

for $f_{ul}=20Hz$ ,

${\lambda }_{min}=1450/20000=0.0725m=7.25cm$