The sound from a single source can reach point O by two different paths. One path is 20.0 m long and the second path is 21.0 m long. The sound destructively interferes at point O. What is the minimum frequency of the source if the speed of sound is 340 m/s?

minimum frequency = 170 Hz

Explanation:

given data

One path long = 20 m

second path long = 21 m

speed of sound = 340 m/s

solution

we get here destructive phase that is path difference of minimum

here  λ is the wavelength of the wave

so path difference will be

21 - 20 =  

λ = 2 m

and

velocity that is express as

velocity = frequency × wavelength    .............1

frequency  =  

minimum frequency = 170 Hz

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