Answer:
frequency 1 = 334.30 Hz
frequency 2 = 1002.92 Hz
Explanation:
Given data
speaker distance y = 0.513 m
microphone distance D = 1.80 m
to find out
lowest two frequencies
solution
we know velocity of sound is 343 m/s
so we consider point x
so at 1st speaker distance from x = D + (y/2)
1st speaker distance from x = 1.80 + (0.513/2) = 2.0565 m .....1
and
at 2nd speaker distance from x = D - (y/2)
2nd speaker distance from x = 1.80 - (0.513/2) = 1.5435 m .........2
so destructive interference from 1 and 2 we know
1st - 2nd = ( m + 0.5 ) wavelength
2.0565 m - 1.5435 m = ( 0+ 0.5) wavelength
wavelength = 1.026 m
so here 1st min frequency will be
frequency 1 = velocity of sound / wavelength
frequency 1 = 343 / 1.026 =334.30 Hz
and
2nd min frequency will be
frequency 2 =
2.0565 m - 1.5435 m = ( 1 + 0.5) wavelength
wavelength = 0.342 m
frequency 2 = velocity of sound / wavelength
frequency 2 = 343 / 0.342 = 1002.92 Hz
