Question

States Newton's formula for the velocity of sound in air. Point out the assumption and hence diserass Laplace's correction.

Answer 1

Newton gave an mathematical relation  to find out the velocity of sound in gas as follows:

v=Bp−−√


or

v=Pp−−√


where

β

 is bulk modulus, P = pressure of gas and p  is the density of the gas.
Assumption:
1) the change in pressure and volume of gas, when sound waves are propagated through a gas in the form of compression, are isothermal in nature.
2) The amount of heat produced during compression  is lost to the surrounding and similarly the amount of heat lost during rarefaction is taken from surrounding.
laplace correction:
The velocity of sound in a gas is corrected further by the laplace, known as laplace correction. the correct formula is

v=γPp−−−√


the value of

γ

 depends on the nature of the gas.