Answer:
Speed is same as that before it entered glass.
Explanation:
Given:
A light ray enters and passes through the glass as shown in the diagram.
We have to analyze its speed.
Speed of light in air is [tex]3\times 10^8\ ms^-^1[/tex] and speed of light in glass is [tex]2.25\times 10^8\ ms^-^1[/tex]
Whenever a light ray enters a glass block or slab there is bending of light at the interface of the two media.
So speed of light will decrease in glass medium and again it passes to the air.
So
Speed of light in air will again increase or will be equivalent to the earlier speed when it was entering the glass block.
Finally
Speed is same as that before it entered glass as it in the same medium (air).
Speed of light is same as that before it entered glass. Option D is correct.
Refraction:
When a light ray move from one medium to another, it slows down, hence bend.
Here, light ray from air enters from the air to glass and emerges out of the glass block.
Speed of light in air is [tex]\bold {3x10^8\ m /s}[/tex]
Speed of light in glass is [tex]\bold {2.25 x10^8\ m /s}[/tex]
Since, the light ray was in the air is same before entering in to the glass.
Therefore, speed of light is same as that before it entered glass.
To know more about light ray,
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