Two stereo speakers are separated by a distance of 2.40 m. A person stands at a distance of 3.20 m directly in front of one of the speakers as shown in figure. Find the frequencies in the audible range (20-2000 Hz) for which the listener will hear a minimum sound intensity. Speed of sound in air `= 320 ms^-1`

Answer

A, B, D

Explanation

A Shown in the ure the path difference
`/_\x=sqrt((3.2)62+(2.4)^2-(3.2))`
Again the wavelength of the either sound waves
gt `=(320/p)`
We know destructive interference will occur.
`If /_\x=((2n+1)lamda)/2`

`rarr sqrt((3.2)^2+(2.4)^2-(3.2))`
`rarr ((2n+1))/2 (320/p)`
Solving we get
`rarr V=(2n+1)400/2`
`=200(2n+1)`
where n=1,2,3...........49(audible region)