How does light travel? (2 points)

Light only travels in a vacuum and travels faster when the sound source is moving.

Light only travels in a medium and light travels faster when a sound source is stationary.

Light can only travel in a vacuum and the speed varies depending on whether the source is moving or stationary.

Light can travel in the air or a vacuum and the speed is constant whether the light source is stationary or moving.

Question

How does light travel? (2 points)
		
Light only travels in a vacuum and travels faster when the sound source is moving.
		
Light only travels in a medium and light travels faster when a sound source is stationary.
		
Light can only travel in a vacuum and the speed varies depending on whether the source is moving or stationary.
		
Light can travel in the air or a vacuum and the speed is constant whether the light source is stationary or moving.

anonymous · Answer

Light, and electromagnetic radiation in general, do not require a medium to spread, meaning it travels in vacuum. Also, the speed of light "c" (299792458m/s) is constant.

anonymous · Answer

light travels in a medium called ether.

anonymous · Answer

The question of how light travels through space is one of the perennial mysteries of physics. In modern explanations, it is a wave phenomenon that doesn't need a medium through which to propagate. According to quantum theory, it also behaves as a collection of particles under certain circumstances. For most macroscopic purposes, though, its behavior can be described by treating it as a wave and applying the principles of wave mechanics to describe its motion.