Two sound waves travelling in the same direction are superposed. Their frequencies are `300 and 302 Hz` and their amplitudes are `0.2 and 0.3 mm`, respectively
a. What is the number of beats per second ?
b. What are the maximum and minimum values of resultant amplitude during the formation of beats ?
c. Calculate the ratio of maximum and minimum intensities of the resultant sound.

Explanation

a. Number of beats//s ` = n_(1) = n_(2) = 302 - 300 = 2`.
b. Maximum amplitude
`A_(max) = a_(1) + a_(2) = 0.2 + 0.3 = 0.5 mm`
Minimum amplitude ,
`A_(min) = a_(1) - a_(2) = 0.3 - 0.2 = 0.1 mm`
c. `(I_(max))/(I_(min)) = ((a_(1) + a_(2))^(2))/((a_(1) - a_(2))^(2)) = ((0.5)^(2))/((0.1)^(2)) = (25)/(1)`
`:. I_(max) : I_(min) = 25 :1`