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Homework Help: Few Mirror Questions

  1. Apr 10, 2005 #1
    I have a few mirror questions. I missed class and didnt get the formulas to do these. If some one could help me out it would be appriciated. The formulas I have in my notes are 1/f = 1/do + 1/di and hi = (ho * di) / do. I dont think I have enough info to use these formulas and im guessinf there is a formula or two I am missing.

    1.)A dentist uses a small mirror of radius 55 mm to locate a cavity in a patient's tooth. If the mirror is concave and is held 10 mm from the tooth, what is the magnification of the resulting image?

    2.)A production line inspector wants a mirror that produces an upright image within magnification of 7.0 when it is located 18.0 mm from a machine part.
    What is its radius of curvature?

    3.)Shiny lawn spheres placed on pedestals are convex mirrors. One such sphere has a diameter of 48 cm. A 12 cm robin sits in a tree 2.3 m from the sphere. Where is the image of the robin? How long is the robin's image?

    4.)The image of the moon is formed by a concave mirror whose radius of curvature is 4.41 m at a time when the moon's distance is 3.80 105 km. What is the diameter of the image if the diameter of the moon is 3480 km?

    5.)A shaving mirror has a radius of curvature of 33.0 cm. When a face is 11.0 cm away from the mirror, what is the magnification of the mirror?
  2. jcsd
  3. Apr 11, 2005 #2


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    Staff Emeritus
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    Gold Member

    You really should show your work when posting here. For standard mirror equations, you'll need to do a web search.
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