Which of these can travel at the speed of light in a vacuum?
A) visible light, radio waves, X-rays, and gamma rays
B) only visible light; all other electromagnetic waves travel slower than the speed of light.
C) visible light, atoms, X-rays, and subatomic particles (e.g., electrons)
D) visible light, infrared radiation, ultraviolet radiation, and subatomic particles (e.g., electrons)

Question

Quizplus · Accepted Answer

All options listed in choice A (visible light, radio waves, X-rays, and gamma rays) are forms of electromagnetic radiation, which travel at the speed of light in a vacuum.

Which of These Can Travel at the Speed of Light