Question

What is the wavelength in air under standard conditions of a compressional wave

whose frequency is 250 per second? Assume that the bulk modulus for air is 1.40

x 106 dyn/cm2 and the density of air is 1.29 g/L.

Answer 1

The speed of sound

$$v=\sqrt{\frac{B}{\rho}}=\sqrt{\frac{1.4*10^5}{1.29}}=329\:\rm m/s$$

The wavelength

$$\lambda=\frac{v}{f}=\frac{329}{250}=1.32\:\rm m$$