For total internal reflection what will be the particular value of ‘i’ and ‘r’
Answers
When a ray of light AO passes from denser medium to rarer medium, light is partly reflected along OB and is refracted at r along OC. As you can see, there are three cases... When the angle of incidence i is increased, r is also increased (As it passes from denser to rarer medium, light is deflected away from the normal NN'). As i is further increased to some higher angle, r becomes 90o and the light ray grazes over the interface which separates the two media. This angle is called the critical angle (say c or θc). As the incident angle is increased above critical angle (i.e) i>c,
r>90o⟹sinθr>1
which is impossible or no refraction is possible. Thus, the ray is reflected into the denser medium itself. This is called Total internal reflection.
According to wave theories, for Total internal reflection to happen:
Light must travel from denser medium to rarer medium.
Angle of incidence should be greater than critical angle (i.e) i>c.
