Question

A bat emits ultrasonic sound of frequency 1000 kHz in air. If this sound meets a water surface, what is the wavelength of : 

(a) the reflected sound 

(b) the transmitted sound ? 

Speed of sound in air = 340 m/s and in water = 1486 m/s.

Answer 1

We are given that frequency of the ultrasonic sound

v = 1000 kHz = 10⁶ Hz

speed of sound in air, v_a = 340 m/s

speed of sound in air, v_a = 340 m/s

v_w = 1486 m/s

(a) The reflected sound is travelling in air. 

Therefore if λa is the wavelength of the reflected wave,

(b) Further, the transmitted wave is travelling through water and as such wavelength of the transmitted wave, i.e.,