Which of the following types of electromagnetic radiation travels at the greatest speed in vacuum?
A. Radio waves
B. X rays
C. Gamma rays
D. All of these travel at the same speed
Correct Answer: D
Explanation:
Electromagnetic radiation, including radio waves, visible light, X-rays, and gamma rays, all travel at the same speed in a vacuum, which is approximately 299,792,458 meters per second. This is due to the fact that the speed of electromagnetic waves is determined by the properties of space rather than the properties of the waves themselves.
While the speed of electromagnetic waves can be altered when they pass through a medium such as air, water, or glass, this is because the properties of the medium affect the speed of the waves. However, in a vacuum, all types of electromagnetic radiation travel at the same speed.
Therefore, statement D is correct in asserting that all forms of electromagnetic radiation travel at the same speed in a vacuum.