Question

List Match Set-I
Column-I contains four situations of a incident ray. Column-II contains property of reflected or refracted ray coming out of the system for any angle of incidence. Case of $TIR$ has to be taken only where there is refraction

	Column-I		Column-II
(A)		(P)	The ray may go through total internal reflection
(B)		(Q)	The ray cannot go through total internal reflection
(C)		(R)	Angle of deviation is ${180}^{\circ }$
(D)		(S)	Angle of deviation can be ${90}^{\circ }$
		(T)	Angle of deviation can be $0^{\circ }$

Which of the following option has the correct combination considering column-I and column-II ?

Answer 1

For (A) : $TIR$ cannot take place
Because incident ray is going rarer to dancer medium this is not condition of $TIR$.
For (B) : Reflected ray becomes parallel if two plane mirrors are at ${90}^{\circ }$.
When mirror are inclined perpendicular $\theta ={90}^{\circ }$
$\delta =360-2\theta$
$\delta =360-180$
$\delta ={180}^{\circ }$
${180}^{\circ }$ means that incident ray of light and reflected ray will be parallel to each other but in opposite direction.
For (C) : At both the places, $TIR$ occurs.
It is clear from figure that light ray is incident normally on surface $AB$. Now when it goes through surface $AC$ there may be a condition of $TIR$ because light is going from dancer to rarer medium and after that by two reflection it comes prism so the total deviation of ray is ${180}^{\circ }$.

For (D) : ${\theta }_c={45}^{\circ }$ and $A={60}^{\circ }$ then $TIR$ can take place
It is clear from figure that light ray is incident on surface $AC$. Now when it goes through surface $BC$ there may be a condition of $TIR$ because light is going from dancer to rarer medium and after that by two reflection it comes prism so the total deviation of ray is ${180}^{\circ }$.