We saw that in Reflection of light,
light bounces off the surface
But sometimes, light does not bounce off the surface
Light goes inside a different medium
This going inside different medium is called refraction
Now, suppose we have Light coming from air into Water
The Light doesn't reflect from water... it goes inside water
And light travels slower in water than air,
So, it changes direction
This changing of direction is called Refraction
Let's define it formally
What is Refraction of Light
The change in direction of light
when it passes from one medium to another
obliquely
is called Refraction of light
Note: - We write obliquely here because light should come at an angle, it should not be perpendicular to the surface
Example 1
Suppose we put a pencil in a glass of water
It appears to be displaced (at the place air and water meet)
This is because of refraction of light
(Light bends when it moves from air to water)
Example 2
Suppose we write something on a piece of paper
We put a glass slab over it
The letter appears to be raised
This is also because of refraction of light
Difference Between Refraction of Light and Reflection of Light
What Causes Refraction of Light?
It is caused by change in Speed of Light in Different Mediums
Explanation
Speed of Light is different in different mediums
Example-Speed of Light is more in Air than in Glass
When light travels from one medium to another (like from air to glass), there is difference in speed of light in 2 mediums
This causes Refraction of light
Questions
Question 1 Page 176 - A ray of light travelling in air enters obliquely into water. Does the light ray bends towards the normal or away from the normal? Why?
