If the temperature of the gas remains constant, then by Boyle’s law PV = constant
That is, P (m/ρ) = constant
p/ρ is a constant, when mass (m) of a gas is constant. If the pressure changes from P to P ′ then the corresponding density also will change from ρ to ρ ′ such that P/ρ is a constant.
In Laplace’s formula √(γP/ρ) is also a constant. Therefore the velocity of sound in a gas is independent of the change in pressure provided the temperature remains constant.
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