What is the frequency of a sound wave in air at 20°C that has a wavelength of 0.4 m?

distance = speed time time

so
wavelength = speed of sound * period T
but
f = 1/T
so
wavelength = speed of sound / f

f = speed /wavelength
look up speed of sound at 20 C in your book (different tables available)

857.5hz?

To find the frequency of a sound wave, we can use the formula:

Frequency (f) = Speed of Sound (v) / Wavelength (λ)

The speed of sound in air at 20°C is approximately 343 meters per second.

Substituting this value along with the given wavelength of 0.4 m into the formula, we can calculate the frequency:

f = 343 m/s / 0.4 m

Simplifying this equation gives:

f = 857.5 Hz

Therefore, the frequency of the sound wave in air at 20°C with a wavelength of 0.4 m is approximately 857.5 Hz.