A plane mirror M is arranged parallel to a wall W at a distance l from it. The light produced by a point source S kept on the wall is reflected by the mirror and produces a patch of light on the wall. The mirroo moves with velocity v towards the wall.
Which of the following statement(s) is`//`are correct?

Options

A. The patch of light will move with the speed `v` on the wall.
B. The patch of light will not move on the wall.
C. As the mirror comes closer the patch of light will become larger and shift away from the wall with speed large than `v` .
D. The widht of the light patch on the wall remains the same.

Answer

b,d

Explanation

Here, `sp=PA` and `SQ=QB`
so, position of `A` and `B` dcedn't depend on separation of mirror from the eall so, the patch `AB` will not move on the wall ` therefore ` `SA` and `SB` are constant
So, `AB` = constant.