Question

How to calculate the wavelength of ultrasonic wave in air?

Answer 1

The frequency, wavelength, and speed of ultrasonic waves in air are related as v = λ * f. So, λ = v / f. The speed of sound in air is 340 m/s

Answer 2

The wavelength of ultrasonic sound waves is given by ⇒  v =  λf

where  λ = wavelength of the wave

            v = velocity

             f = frequency

Here , we know that

• The frequency of an ultrasonic wave is 20kHz.

• The velocity of an ultrasonic wave in air is 340 m/s.

Therefore ,   λ = $\frac{v}{f}$ =  $\frac{340}{ 20 * 10^{3} }$

                        = 17 * $10^{-3}$m

                         =1.7 cm

The wavelength of ultrasonic sound waves is 1.7 cm