Question

A bat emits ultrasonic sound of frequency 1000 kHz in air. If the sound meets a water surface, what is the wavelength of (a) the reflected sound, (b) the transmitted sound? Speed of sound in air is 340 m s –1 and in water 1486 m s–1 .

Answer 1

Frequency of the ultrasonic sound, ν = 1000 kHz = 106 Hz

Speed of sound in air, va = 340 m/s

The wavelength (λr) of the reflected sound is given by the relation:

$λ_r=\frac{v}{v}$

$=\frac{340}{10^6}=3.4×10^{-4}$ m

Frequency of the ultrasonic sound, ν = 1000 kHz = 106 Hz

Speed of sound in water, vw = 1486 m/s

The wavelength of the transmitted sound is given as:

$λ_1=\frac{1486}{10^6}=1.49*10^{-3}\,m$