Question

Let us assume that a light ray inside a glass medium falls on the glass-air interface at an angle of incidence $\theta $. The reflected $\left( R \right)$ and transmitted $\left( T \right)$ intensities, both as functions of $\theta $ are plotted. The correct graph will be given as,
A.

B.

C.

D. none of the above

Answer 1

Hint: The critical angle is defined as the angle of incidence where the angle of refraction is perpendicular to the normal. The light should travel from an optically denser medium to an optically less dense medium. The angle of incidence is found to be equal to the critical angle when the angle of refraction is equivalent to $90{}^\circ $. This all will help you in solving this question.

Complete answer:
As we all know, above the critical angle, there will be total internal reflection taking place where the refracted ray will get completely reflected. In this case the reflection will be $100%$ and transmission will be occurring at $0%$.
This condition has been satisfied in the options B and C. so now let us consider only these two options. When we look in to option B, the transmission has been shown as $100%$ at an angle given as,
$\theta =0{}^\circ $
This is not true. Therefore option B will not be the accurate answer for this question. From the options given, therefore we can say that the option C is the only one which is true.

Hence the answer is given as option C.

Note:
Total internal reflection is a phenomenon in physics where the complete reflection of a ray of light within a medium like the water or glass from the surrounding surfaces back into the medium. This phenomenon will be happening when the angle of incidence is higher than the critical angle of the whole system.