Chapter - 5 Sound

Q&A -Ask Doubts and Get Answers



A person has a hearing range from 20 Hz to 20 kHz. What are the typical wavelengths of sound waves in air corresponding to these two frequencies? Take the speed of sound in air as 344 m/s.


Given: The frequency range of hearing is 20 Hz to 20 kHz and the speed of sound is 344 m/s.

To Find: The range of wavelength between the frequencies 20 HZ and 20 kHz.

Solution: We know the relation between the speed of sound, its wavelength and the frequency as

Speed = Wavelength 	imes frequency

v =lambda 	imes 

frac { v }{ 
u }= lambda

Now, using this relation for calculating wavelength of a sound having a frequency of 20Hz

lambda = frac { v }{ 
u }

lambda = frac { 344 }{20} = 17.2 m


Now, for the sound of frequency 20 kHz or 20000 Hz, the wavelength would be:

lambda = frac { v }{ 
u }

lambda = frac { 344 }{20000} = 0.0172 m

Hence, the wavelength range would be from 0.0172 m to 17.2 m.

Related Questions for Study

What our students and parents say about us!

Choose EduSakshamยฎ
Embrace Better Learning