Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Converging Lens Magnification Problem

  1. Aug 25, 2004 #1
    What am I missing here?

    A person looks at a gem using a converging lens with a focal length of 15.0 cm. The lens forms a virtual image 26.0 cm from the lens. Determine the magnification.

    (1/p)+(1/q) = (1/f)
    q=26 cm
    f=15 cm

    (1/15)-(1/26)= Ans^-1 = 35.5 cm (p)

    Magnification= -(q/p)
    M= -(26/35.5)
    M= -0.733

    Answer [-.733] has been marked wrong. What did I do?
  2. jcsd
  3. Aug 25, 2004 #2

    Doc Al

    User Avatar

    Staff: Mentor

    check your sign convention

    Your sign convention is incorrect. "q" for a virtual image is negative.

    Welcome to PF, by the way.
  4. Aug 25, 2004 #3
    whoa thanks

    i apologize, i knew that...just dumb tonight

    thanks for the welcome
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook