Question

Two sources of sound placed close to each other, are emitting progressive waves given by y1=4sin600πt and y2=5sin608πt

Answer 1

1max by 1min

a1+a2 by a1-a2 square

4+5 by 4-5=81by1 ans

Answer 2

Answer:

4 beats per second with intensity ratio 81 : 1 between waxing and waning

Explanation:

 y1  =  4sin600 (Given)

y2 = 5  sin  608πt (Given)

Comparing with the general equation

y = asin2πft we will get f1 as 300Hz and f2 as 304Hz

Thus,

2πf₁ = 600π , f₁ = 300 …(1)

2πf₂ = 608π , f₂ = 304 …(2)

| f₁ – f₂ | = 4 beats

Imax / Imin = (A₁ + A₂)² / (A₁ – A₂)²

= (5 + 4)² / (5 – 4)²

= 81/1

Where, A₁ , A₂ are amplitudes of given two sound waves.

Hence, there will be 4 beats per second with intensity ratio 81 : 1 between waxing and waning