Question

What frequency of sound traveling in air at 20 degrees C has a wavelength equal to 1.6 m, the average height of a person? (Hz)

Answer 1

Let's first find the speed of sound in air at $20^{\circ}C$:

$$v=(331.3+0.606\cdot\theta)=(331.3+0.606\cdot20^{\circ}C)=343.42\ \dfrac{m}{s}.$$

Finally, we can find the frequency of the sound from the wave-speed formula:

$$v=f\lambda,$$ $$f=\dfrac{v}{\lambda}=\dfrac{343.42\ \dfrac{m}{s}}{1.6\ m}=215\ Hz.$$