00:01
So given in the question, two plane mirrors are inclined to each other at an angle alpha.
00:05
Let's say this is mirror m1 and this is mirror m2.
00:09
They intersect along a line through o and are inclined at an angle alpha.
00:14
The line of intersection is perpendicular to the plane of the slide.
00:18
So it is in this question we need to show that any ray whose plane of incidence is perpendicular to the line of intersection.
00:25
That means if the line of intersection is perpendicular to the plane of this slide, then any ray drawn on the slide will be perpendicular to the line of intersection.
00:38
So any ray whose plane of incidence is perpendicular to the line of intersection of the two mirrors is deviated by two reflections by an angle delta that is independent of the angle of incidence.
00:52
And we have to find this deviation delta in terms of this angle alpha.
00:58
So let us consider ray ab incident onto the mirror m1 at b, letting reflected along b c and finally reflected along c -d -e by the mirror m2.
01:10
Let the ray ab be reflected at an angle i and after reflection ray b -c as an angle of incidence are responding to mirror m2...