1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: Image Projection

  1. Feb 25, 2006 #1
    "A 35 mm slide (picture actually 24*36 mm) is to be projected on a screen 1.8*2.7 m placed 9 m from the projector. What focal length lens should be used if the imageis to cover the screen?"

    I was trying to do this problem using the formula (1/do)+(1/di)=(1/f), but hten i realized i dont have the object distance, so what formula can i use?
  2. jcsd
  3. Feb 25, 2006 #2
    There is a formula for magnification? Try if you remember.
  4. Feb 25, 2006 #3


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Try http://hyperphysics.phy-astr.gsu.edu/ this usually gives good information. I believe you assume that object distance, which in this case is the slide, is zero.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook