Question

beam of has to hit midpoint of wall AB after reflection from mirror .Find distance of point from A where beam must strike mirror.How to solve it? fig. is in attachment.

Answer 1

It is common sense that since angle of incidence =angl of ref. thus if ray hits opposite wall at l.t. 2.5 from left end it will fall back. Thus AX l.t. 2.5. by ratio proportion of similar ∆s 1.5/x=3/(5-x) 4.5x=7.5 x=5/3. ok