Question

For a wave to undergo total internal reflection ( critical angle and i incident angle)

• A. light moves from rarer to denser medium and $i<i_C$
• B. light moves from denser to rarer medium and $i<i_C$
• C. light moves from rarer to denser medium and $i>i_C$
• D. light moves from denser to rarer medium and $i>i_C$

Answer 1

The correct option is D light moves from denser to rarer medium and $i>i_C$

When a ray of light travelling from a denser medium to a rarer medium is incident at the surface of separation of the two media at an angle greater than the critical angle for the media, there is no refraction; rather the whole of the incident ray is internally reflected. This phenomenon is known as total internal reflection.

Condition of total internal reflection: The conditions to be satisfied for total internal reflection are as follows -

1) Light must travel from a denser to a rarer medium.

2) The angle of incidence($i$) must be greater than the critical angle($i_c$) the two media.

So, the correct answer is - (D) light moves from denser to rarer medium and $i>i_c$