Two sources of sound placed close to each other are emitting progressive waves given by `y_1=4sin600pit` and `y_2=5sin608pit`. An observer located near these two sources of sound will hear:

Options

A. 4 beats per second with intensity ratio 81:1 between waxing and waning
B. 4 beats per second with intensity ratio 25:16 between waxing and waning
C. 8 beats per second with intensity ratio 25:16 between waxing and waning
D. 8 beats per second with intensity ratio `81:1` between waxing and waning

Answer

A

Explanation

`(I_1)/(I_2)=((A_1+A_2)^2)/((A_1-A_2)^2)=(81)/(1)`
Beat frequency `=304-300=4Hz`