What is total internalreflection ? What is the meaning of critical angle ? What are the necessary conditions for total internal reflection ?
Write the relation between critical angle and refractive index of the medium.

Explanation

Total internal reflection is the phenomenon of reflection of light when it is travelling in a deser medium, strikes the interface separating. The denser medium and the rarer madium at an angle greater than critical angle.

We know that when a ray travels from denser to rarer medium,the refracted ray is bent away from the norma. At point C, the refracted ray makes an angle `90^@` with the normal and is called critical angle. So critical angle is the angle of incidece in the denser medium for which angle fo refraction is `90^@`.
Conditions for total internal reflection
(i) Rayy of light proceed from denser medium to rarer medium.
(ii) Angle of incidence should be greater than critical angle.
Relation between C and `mu`.
`""^2mu_1 = (sin C)/(sin90^@) = sin C`
`or ""^1mu_2 = 1/(sinC)`