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Homework Help: Light, lenses, and mirrors

  1. Jan 17, 2008 #1
    1. The problem statement, all variables and given/known data
    I have a final tomorrow, and I there are a couple questions that I don't know.

    When the angle of incidence is the critical angle, the angle of refraction will be?

    If a screen is moved 3 times the distance from a light source, what will the intensity on the screen be reduced to?

    A ray of light is incident at 38º on a curved mirror. At what angle will the reflected ray leave the mirror?

    2. Relevant equations

    n1sin90º=n2sin(critical angle)
    I'm not sure which formula to use for the one regarding light intensity, and for the last, I drew it out.
  2. jcsd
  3. Jan 17, 2008 #2
    90 degree [according to the definition of critical incident angle]

    2. don't know

    3. 38 degree [ according to the laws of reflection of light: the reflected angle is equal to the incident angle]
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