00:01
Here in this given problem this is the rectangular hall, this front wall that is a plain mirror, the left side this is a wall, width of the room 3 .0 meter, length of this room 5 .0 meter.
00:25
This is a laser light starting from the left corner of the room and making an angle phi with the wall of this room and this angle should be such that after reflecting back from this mirror if this ray of light goes like this it should strike at the midpoint of this wall, the far wall.
01:04
So, if the complete length of this wall that is 3 .0 meter then here it is 1 .5 meter.
01:17
Suppose the distance of point where this laser light strike the mirror, suppose this is x meter from the left end and this is y meter from the right end, then if this angle is phi.
01:33
So, this angle will also be phi and here that is the angle of incidence which will be 90 minus phi.
01:43
So, angle of reflection that will also be 90 minus phi.
01:47
So, this angle is also phi...