When a flashlight beam passes from the air through a car window, the speed of the light wave changes due to the difference in the refractive indices of air and glass. Let's analyze this step-by-step using the provided speeds of light in different media:
1. Speed of Light in Air: According to the table, the speed of light in air is [tex]\( 299,700,000 \, \text{m/s} \)[/tex].
2. Speed of Light in Glass: According to the table, the speed of light in glass is [tex]\( 200,000,000 \, \text{m/s} \)[/tex].
To determine what happens to the speed as light travels from air to glass, we compare these two values:
- The speed of light in air ([tex]\( 299,700,000 \, \text{m/s} \)[/tex]) is higher than the speed of light in glass ([tex]\( 200,000,000 \, \text{m/s} \)[/tex]).
Since the speed of light in glass is less than that in air, the speed of the light wave decreases as it passes from air into the glass.
Therefore, the correct answer is:
B. It decreases.
