What term describes the constant 299,792,458 meters per second in a vacuum?

What term describes the constant 299,792,458 meters per second in a vacuum?

• A. Mass
• B. Frequency
• C. Acceleration
• D. Speed of light

Answer: (D)

Light travels through empty space at a fixed, universal speed. This constant is the speed of light, and its value is defined exactly as 299,792,458 meters per second. The meter itself is defined by how far light travels in vacuum in a specific fraction of a second, so the speed of light is fixed by definition. That makes this term the best description of the given quantity. Mass, frequency, and acceleration refer to different ideas—mass measures matter, frequency is cycles per unit time, and acceleration is how velocity changes over time—so they don’t describe how fast light moves.

Light travels through empty space at a fixed, universal speed. This constant is the speed of light, and its value is defined exactly as 299,792,458 meters per second. The meter itself is defined by how far light travels in vacuum in a specific fraction of a second, so the speed of light is fixed by definition. That makes this term the best description of the given quantity.

Mass, frequency, and acceleration refer to different ideas—mass measures matter, frequency is cycles per unit time, and acceleration is how velocity changes over time—so they don’t describe how fast light moves.