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

Reflection and Refraction Compared - Teachoo.jpg

 

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)

Refraction - Example 1 - Pencil in water.jpg

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

Text appears higher through glass slab - Teachoo.jpg

Difference Between Refraction of Light and Reflection of Light

Check here

 

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?

View Answer

  1. Class 10
  2. Chapter 10 Class 10 - Light - Reflection and Refraction

About the Author

Davneet Singh's photo - Teacher, Computer Engineer, Marketer
Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.