Finding the Angle of Incidence in a Plane Mirror: Reflection of Light Homework

[TheHamburgler1]

Homework Statement

A person stands 3.6m in front of a wall that is covered floor to ceiling with a plane mirror. His eyes are 1.8m above the floor. He holds a flashlight between his feet and manages to point it at the mirror. At what angel of incidence must the light strike the mirror so the light will reach his eyes?

Homework Equations

angle of incidence=angle of reflection

The Attempt at a Solution

I don't know what equation to use to get the answer

 

[link2001]

Try drawing a picture of the problem. Diagrams are your best friend in optics problems.

 

[hage567]

Try drawing a picture of the problem. Diagrams are your best friend in optics problems.

Excellent advice, link2001!

Think trigonometry.

 

[nickthrop101]

yep, use trigonomety, draw a triangle, put x as the angle to the normal, the normal length is infinite but draw it as 3.6, and the height from the feet of the person , so that makes theta= inverse of tan( 0.9 divided by 3.6), that should give the angle to the normal. :D