Question

10 watt source of sound of frequency 1000 Hz sends out waves in air. The displacement amplitude at a distance of 10m from the source is (speed of sound in air = 340 m/s and density of air = 1.29 kg/m3)​

Answer 1

Given :

Power of source = 10Watt

Frequency = 1000 Hz

To find :

The displacement ampitude at a distance of 10m from source

Solution:

• we know that  ,Displacement Amplitude = (1/2πfr)×√P/2πρv)

• Amplitude = (1/2πfr)×√P/2πρv)

                =  (1/2π×1000×10)×√10/2π×129×340)

                = 0.96μm

The displacement ampitude at a distance of 10m from source is 0.96μm