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Reflection of light

  1. Mar 18, 2007 #1
    1. The problem statement, all variables and given/known data

    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?

    2. Relevant equations
    angle of incidence=angle of reflection

    3. The attempt at a solution

    I don't know what equation to use to get the answer
  2. jcsd
  3. Mar 18, 2007 #2
    Try drawing a picture of the problem. Diagrams are your best friend in optics problems.
  4. Mar 18, 2007 #3


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    Homework Helper

    Excellent advice, link2001!

    Think trigonometry.
  5. Mar 13, 2011 #4
    yep, use trigonomety, draw a triangle, put x as the angle to the normal, the normal length is infinate 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
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