Estimate the speed of sound in air at standard temperature and pressure. The mass of 1 mole of air is `29.0xx10^(-3)kg`, `lambda` for air `=7//5`.

Explanation

Density of air is
`rho = ("Mass of 1 mole of air")/("Volume of 1 mole of air")`
`= (29.0 xx 10^(-3) kg)/(22.4 xx 10^(-3) m^(3))`
`= 1.29 kg//m^(3)`
At S.T.P., `P = 1.01 xx 10^(5)` Pa
(i) Using Newton.s formula, speed of sound in air at S.T.P. is
`upsilon = sqrt((P)/(rho)) = sqrt((1.01 xx 10^(5))/(1.29)) = 280` m/s
(ii) For air r = 1.4, using Laplace.s formula, speed of sound in air at S.T.P. is
`upsilon = sqrt((gamma P)/(rho)) = sqrt((1.4 xx 1.01 xx 10^(5))/(1.29)) = 331.5 m//s`