Question

Density differences in different materials are able to change the _____________ of a wave.

Answer 1

Answer:

Wavelength and speed both depend on the material of the medium.

Explanation:

Let $f$ denote the frequency of a wave. Let $v$ denote the speed of that wave in a given medium. Let $\lambda$ denote the wavelength of that wave in this medium.

The frequency $f$ of a wave stays the same regardless of the material of the media. However, the speed $v$ of a wave indeed depends on the material of the medium (density of the medium, etc.)

$\lambda = v / f$ and $f$ stays the same regardless of the medium. Thus, the wavelength $\lambda$ of this wave in a given medium would be proportional to the speed $v$ in that medium.

For example, the speed of sound in materials with a larger density (e.g., water) is generally larger than that in materials with lower density (e.g., air.)

When a sound wave travels from air into water, the frequency $f$ of this wave would stay the same. However, since the speed $v$ of the wave would increase, the wavelength $\lambda$ of this wave would also increase.