Question

The wavelengths of two sound waves in air are `81/173`m and `81/170`m. They produce 10 beats per second. Calculate the velocity of sound in air

Answer 1

Data: `lambda_1 = 81/173`m = 0.468 m

`lambda_2 = 81/170 m = 0.476 m`

Δn = 10 beats

Formula:

Δn = n₁ - n₂

`= V/lambda_1 - V/lambda_2`

Δn = n₁ - n₂

`= V[1/lambda_1 - 1/lambda_2]`

`10 = V[173/81-170/81]`

`10 = V[3/81]`

`10 = V(10xx81)/3`

V = 270 m/s