$$\lambda = \frac{v}{f}$$
where:
* $$\lambda$$ is the wavelength in meters
* $$v$$ is the speed of sound in meters per second
* $$f$$ is the frequency of the sound wave in hertz
Substituting the given values into the formula, we get:
$$\lambda_{1200} = \frac{343\text{ m/s}}{1200\text{ Hz}} = 0.286\text{ m}$$
$$\lambda_{3000} = \frac{343\text{ m/s}}{3000\text{ Hz}} = 0.114\text{ m}$$
The difference in wavelengths is:
$$\Delta \lambda = \lambda_{3000} - \lambda_{1200} = 0.114\text{ m} - 0.286\text{ m} = -0.172\text{ m}$$
The negative sign indicates that the wavelength of the 3000 hertz note is shorter than the wavelength of the 1200 hertz note.