2. OBJECTIVES The students
Understand the phenomena of total internal reflection
Appreciate the applications of total internal reflection in various fields
Develop logical reasoning ability
Are Exposed to the use of Total Internal Reflection in modern communication systems

3. The students already know The phenomenon of Reflection and Refraction
Previous Knowledge
The students already know
The phenomenon of Reflection and Refraction
Laws of Reflection and Refraction

4. What is Refraction?
Refraction is the bending of light at the surface of separation between two transparent media when light passes from one medium to another
Light bends towards the normal when it travels from a rarer to denser medium
Light bends away from the normal when it travels from a denser to rarer medium

5. Consider a ray of light travelling from a denser to rarer medium
The ray of light bends away from the normal in the rarer medium
Rarer medium
Denser medium

6. Now let’s increase the angle of incidence
The refracted ray bends more away from the normal and nears the surface of separation.
Rarer medium
Denser medium

7. Now for a particular value of angle of incidence the refracted ray grazes the surface of separation
This angle of incidence inside the denser medium, for which the refracted ray just grazes the surface of separation is called the critical angle for the pair of media.
critical angle C

8. TOTAL INTERNAL REFLECTION
What happens If the angle of incidence inside the denser medium is greater than the critical angle? ?
Then the ray is not refracted, But it is totally reflected internally obeying the laws of reflection. This phenomenon is called TOTAL INTERNAL REFLECTION
TOTAL INTERNAL REFLECTION

9. CONDITIONS FOR TOTAL INTERNAL REFLECTION
The light must travel from a denser to a rarer medium
The angle of incidence must be greater than the critical angle for the pair of media.

10. APPLICATIONS OF TOTAL INTERNAL REFLECTION
TOTAL REFLECTING PRISMS
SPARKLING OF DIAMOND
SHINING OF AIR BUBBLE IN WATER
MIRAGE
OPTICAL FIBRES

11. TOTAL REFLECTING PRISMS
THEY ARE ISOCELES RIGHT ANGLED PRISMS

12. USES OF TOTAL REFLECTING PRISMS
TO ROTATE A RAY OF LIGHT THROUGH 90

13. TO ROTATE A RAY OF LIGHT THROUGH 180

14. TO ERECT AN INVERTED IMAGE OR VICE VERSA

15. SPARKLING OF DIAMOND

16. SHINING OF AIR BUBBLES IN WATER

17. MIRAGE

18. OPTICAL FIBRES

19. ACKNOWLEDGEMENTS Thank You
NCERT Text Book for Class XII and for content
Thank You