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Mix questions on mirror formula and magnification


A dentist uses a small concave mirror of focal length 3.0 cm and places it 2.0 cm from a patient's tooth to look for cavities.
What is the magnification, m of the tooth's image produced by the mirror?
Note: Let's write the answer with the correct sign.
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3/5
  • a simplified improper fraction, like 7/4
  • a mixed number, like 1 3/4
  • an exact decimal, like 0.75
  • a multiple of pi, like 12 pi or 2/3 pi