Question

The speed of light ________ when light goes through glass.

a) decreases marginally
b) decreases substantially
c) increases marginally
d) increases substantially
e) none of these


the answer isnt in my book and i cant find it on the internet. i think its b but its a guess

Answer 1

The speed of light decreases substantially when it goes through glass, slowing down to about two-thirds of its velocity in a vacuum. This change in speed results in refraction, which includes bending of the light ray and a decrease in its wavelength.

Step-by-step explanation:

The speed of light decreases when light goes through glass. This is a well-known physical phenomenon due to the refraction of light. When light passes from a less dense medium, like air, into a denser medium, like glass, it slows down. The correct option is b) decreases substantially.

This decrease in speed also results in a bending of the light ray towards the normal. The extent of the decrease varies by material, but in the case of glass, the speed of light can slow down to about two-thirds of its velocity in a vacuum. Thus, while 'substantially' can be a relative term, in the context of the change from air to glass, the decrease is significant enough to be indeed considered substantial.

Upon entering a medium like glass, light does not only slow down but also experiences a decrease in wavelength. This is consistent with the principle that the speed of light in a vacuum is its maximum possible value, and any other medium will slow it down to some degree due to the medium's refractive index.

Answer 2

What happens when the light hits the glass depends on what it was in before it hit the glass.

WHILE it's in the glass, the speed of light doesn't change.