posted by rick .
A person stands 4.4 m in front of a wall that is covered floor-to-ceiling with a plane mirror. His eyes are 1.9 m above the floor. He holds a flashlight between his feet and manages to point it at the mirror. At what angle of incidence must the light strike the mirror so the light will reach his eyes?
The beam must strike the mirror half way up from his feet to his eyes. The angle is incidence is therefore
tan^-1 [(1/2)*1.9/4.4] = tan^-1 .21591
= 12.2 degrees