Recap Notes: Refraction of light

Recap Notes: Refraction of light

1. What is meant by refraction of light?
   When a ray of light passes from one medium to another, it bends.  This bending of light is called "refraction".
   
2. What is meant by "highly dense medium"?
   If light travels slower in a medium than another medium, then this medium is described as " highly dense medium" than the other.
   
3. What is meant by "less dense medium"?
   If light travels faster in a medium than another medium, then this medium is called less denser than the other
4. How lights bends when light moves from medium to another?
   When a ray of light enters a denser medium, it is bent towards the normal.
   When a ray of light enters a less dense medium, it is bent away from the normal.
5. Show when a ray of light enters a denser medium, it is bent towards the normal.
   
6. Show when a ray of light enters a less dense medium, it is bent away from the normal.
   
7. What is meant by index of refraction?
   There is an index of refraction (n) is defined as the speed of light in vacuum divided by the speed of light in medium.
8. Define the followings: incident angle, refraction angle, incident ray, reflected light, Normal?
     incident angle the angle between normal and incident ray
     refraction angle the angle between normal and refracted ray
     incident ray the light ray that is coming from light source and strikes the boundary surface.
     reflected light the light ray that emerges from the second medium 
     Normal the perpendicular line on the boundary surface.
9. What is meant by critical angle?
   The critical angle is the angle of incidence for which the refracted ray is at 90 degrees with the normal.
   
10. What is meant by internal reflection and total internal reflection of light?
    Internal reflection occurs when the incident angle is equal to or less than the critical angle where some of the light ray will be internally reflected and some refracted.

The green region shows the refracted light area. The cyan region represented the reflected light are.

               

11. Total internal reflection occurs occurs when the incident angle is always greater than the critical angle where all light ray will be internally reflected.
     
12. List two applications in our lives which uses the concept of critical angle and the total internal reflection.
    1- Cameras: Cameras uses prisms to reflect light instead of mirror.
     
    2- Fiber optics: Fiber optic are thin, flexible glass rods used to carry light.  The light enters the fiber optics at angle greater than the critical angle of the fiber. In side the fiber light is totally reflected from one side to the other until it leaves the fiber from the other end.