1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

What is the focal length of the lens? given magnification and distance

  1. Apr 13, 2013 #1
    1. The problem statement, all variables and given/known data
    A biology student wishes to examine a bug at a magnificaiton of +5.00 by looking through a single lens. the student wants the image of the bug to be a distance of 25cm from the lens. what is the focal length of the lens?

    Answer:+6.25cm
    2. Relevant equations
    m=-d(image)/d(object)
    1/f=[itex]\frac{1}{d(object)}[/itex]+[itex]\frac{1}{d(image)}[/itex]


    3. The attempt at a solution
    first i solve for distance of object, d(object), by using the first equation:
    d(object) = (25x10-2)/5

    then i calculated focal length by using the second equation
    f = ((1/0.5) + (1/0.25))-1 = 0.041667

    i dont know what im doing wrong
     
  2. jcsd
  3. Apr 13, 2013 #2
    This is a simple magnifying glass using a converging lens.
    The image is VIRTUAL....what does this mean about the image distance in the equation???
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted