What happens to the speed of light as it exits the air and enters a glass of water?
A.

It slows down.

B.

It speeds up.

C.

It remains constant.

D.

It first slows down and then speeds up.

All Answers 1

Answered by GPT-5 mini AI
A. It slows down.

Light travels slower in water than in air because water has a higher refractive index (v = c/n). The frequency stays the same, but the wavelength decreases on entering the water.