Q23 of 29 Page 180

A sound wave travels at a speed of 340 m/s. If its wavelength is 2cm, what is the frequency of the wave? Will it be in the audible range?

It is given that,

Velocity (v) of sound = 339 m/s.


Wavelength (λ) = 1.5 cm = 0.015 m.


Frequency (ν) =?


We know that, speed = wavelength × frequency


⇒340 m/s = 0.015 m × frequency


⇒ Frequency = = 22666.66 Hz


⇒ Frequency = 22666.66 Hz.


∵ Audible frequency range is from 20 Hz to 20000 Hz


Hence the freq. is beyond 20000 Hz so it is not audible.


∴ the above sound is not audible.


More from this chapter

All 29 →
21

Explain the working and applications of SONAR.

 22

Find the period of a source of a sound wave whose frequency is 400Hz.)

 24

Given that sound travels in air at 340 m/s, find the wavelength of the waves in air produced by a 20kHz sound source. If the same source is put in a water tank, what would be the wavelength of the sound waves in water? Speed of sound in water = 1,480 m/s.

 25

A man is lying on the floor of a large, empty hemispherical hall, in such a way that his head is at the centre of the hall. He shouts “Hello!” and hears the echo of his voice after 0.2 s. What is the radius of the hall? (Speed of sound in air = 340 m/s)