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: Light, Mirrors, Lenses, immediate help required!

  1. May 31, 2005 #1
    Hello, here is the problem i am having trouble with. The sun falls on a concave mirror and forms an image 3 cm from the mirror. If an object 24mm high is placed 12 cm from the mirror, where will its image be formed? So far, i have decided that since 1/f = 1/do + 1/di...
    1/f = 1/do + 1/3 = 1/12 + 1/di
    I also decided that hi/2.4 = -di/12... The problem is...even if i solve for di in terms of hi and plug that into my first equation i dont have enough information to solve for do. Im stuck and this problem is due tomorrow... please help
  2. jcsd
  3. May 31, 2005 #2


    User Avatar
    Science Advisor
    Homework Helper

    You need to use the "sun" information to find the focal length of the mirror. The sun is an object at distance ___________ that forms an image at 3cm. What is f?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook