The table displays the velocity of light in three different states of matter.

Question

Material Speed (meters/second)
air 300,000,000
water 220,000,000
glass 200,000,000
When would the speed of light decrease?
(1 point)
When light transitions from water to air.
When light transitions from glass to air.
When light moves from glass to water.
When light moves from air into water.

Answer 1

The speed of light decreases when it moves from a medium with a higher speed of light to a medium with a lower speed of light.

Based on the table provided:

• Speed of light in air: 300,000,000 m/s
• Speed of light in water: 220,000,000 m/s
• Speed of light in glass: 200,000,000 m/s

From this information, we can assess the transitions:

1. From water (220,000,000 m/s) to air (300,000,000 m/s): Speed increases.
2. From glass (200,000,000 m/s) to air (300,000,000 m/s): Speed increases.
3. From glass (200,000,000 m/s) to water (220,000,000 m/s): Speed increases.
4. From air (300,000,000 m/s) to water (220,000,000 m/s): Speed decreases.

Therefore, the correct answer is: When light moves from air into water.