and making use of the ideal gas law, it follows that
(1.20)
Thus, for ideal gases the speed of sound is proportional to the square root of the absolute temperature.
For example, for air at with and , it follows that
The speed of sound in air at various temperatures can be found in Appendix B
1Tables B.3 and B.42. Equation 1.19 is also valid for liquids, and values of can be used
to determine the speed of sound in liquids. For water at and
so that or As shown by the figure in the margin, the
speed of sound in water is much higher than in air. If a fluid were truly incompressible 1Ev q2