Which statement about light is false?

Which statement about light is false?

• A. Light can be bent by refraction
• B. Light can be reflected
• C. Light travels at the same speed in all media
• D. Light can be absorbed by surfaces

Answer: (C)

Light speed depends on the medium because light interacts with the material and slows down when it enters substances with higher optical density. In vacuum light travels at about 3.00 x 10^8 m/s, but in water it slows to around 2.25 x 10^8 m/s and in glass to roughly 2.0 x 10^8 m/s. This variation is what causes refraction: when light crosses a boundary into a different medium, a change in speed changes its direction, so the wave bends. Light can also be reflected, where a portion bounces off the surface instead of entering the material, and it can be absorbed, where energy from the light is taken up by the material rather than transmitted or reflected. Since the speed isn’t the same in every medium, the statement claiming constant speed everywhere is false.

Light speed depends on the medium because light interacts with the material and slows down when it enters substances with higher optical density. In vacuum light travels at about 3.00 x 10^8 m/s, but in water it slows to around 2.25 x 10^8 m/s and in glass to roughly 2.0 x 10^8 m/s. This variation is what causes refraction: when light crosses a boundary into a different medium, a change in speed changes its direction, so the wave bends.

Light can also be reflected, where a portion bounces off the surface instead of entering the material, and it can be absorbed, where energy from the light is taken up by the material rather than transmitted or reflected. Since the speed isn’t the same in every medium, the statement claiming constant speed everywhere is false.