A point source of light \(S\), placed at a distance \(60 \,cm\) infront of the centre of a plane mirror of width \(50 \,cm\), hangs vertically on a wall. A man walks infront of the mirror along a line parallel to the mirror at a distance \(1.2\, m\) from it (see in the \(figure\)). The distance between the extreme points where he can see the image of the light source in the mirror is \(\ldots \ldots \ldots\, cm.\)

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.