Two standing bodies producing progressive waves are given by
` y_(1) = 4 sin 400 pi t and y_(2) = 3 sin 404 pi t`
One of these bodies situated very near to the ears of a person who will hear :

Explanation

The equation of progressive waves are:
`y_(1)=4sin(400pit), and `
`y_(2)=3sin(404pit)`
`:. a =4 and b=3`
`omega_(1)=2pin_(1)=400pi,n_(1)=200Hz`
`omega_(2)=2pin_(2)=404pi,n_(2)=202Hz`
No. of beats `//` sec `=n_(2)-n_(1)=202-200=2`
`(I_(max))/(I_(min))=((a+b)^(2))/((a-b)^(2))=((4+3)^(2))/((4-3)^(2))=(49)/(1)`