Question

1. how does density impact the speed of light waves? 4. what type of wave travels fastest in space? why?

Explanation:

1. The speed of light waves decreases as the density of the medium increases. In a denser medium, light interacts more frequently with atoms or molecules, causing it to slow down. For example, light travels slower in water (denser) than in air.
2. Electromagnetic waves travel fastest in space because they do not require a medium to propagate. In a vacuum (space), electromagnetic waves such as light travel at the speed of light ($c = 3\times10^{8}$ m/s), while mechanical waves like sound waves cannot travel in a vacuum as they rely on particle - to - particle interaction.

Answer:

1. The speed of light waves decreases in denser media due to more interactions with particles.
2. Electromagnetic waves; they don't need a medium and travel at the speed of light in a vacuum.