An ultrasonic transducer used in sonar produces a frequency of 40 kHz. If the velocity of the sound wave in seawater is 5050 ft/s, what is the wavelength ?
The transducer is made to emit a short burst ofsound and is then turned off. The receiver is turned on. The pulse is reflected from a lurking submarine and received 5.0 s after it was first emitted. How far away is the submarine ?

Explanation

`v = n lambda`
or 5050 = 40000 `lambda`
or `lambda` = 0.126 ft
`v = (2d)/(t)`
or `5050 = (2d)/(5.0)`
or d = 12600 ft`