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Homework Help: Image formed by concave mirror; completed need someone to check

  1. Mar 1, 2010 #1
    1. The problem statement, all variables and given/known data

    A person accidentally bit his tongue and wants to examine the bite by using a concave mirror. The mirror is placed 10 cm from the bite with the result that a virtual image of the bite appears 4 times actual size. Find the parameters s (distance from object to mirror), s' (distance from mirror to image), and R (radius of convex mirror).

    2. Relevant equations
    1/s + 1/s' = 1/f ; f=focal length
    Magnification = -s'/s
    f = R/2

    3. The attempt at a solution

    i got s = 10 cm
    then using magnification formula (4 = -s'/s)
    i got s' = -40 cm (negative b/c its a virtual image)
    i then got focal length = 13.3333 using formula 1
    so if f=R/2; R = 26.6667 cm

    any input would be appreciated
  2. jcsd
  3. Mar 1, 2010 #2
    Hi hodgepodge

    I think you got it right
  4. Mar 1, 2010 #3


    User Avatar
    Homework Helper

    Your solution is correct.
  5. Mar 2, 2010 #4
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