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: Concave mirror

  1. Apr 2, 2009 #1
    concave mirror!!!

    1. The problem statement, all variables and given/known data

    The real image produced by a concave mirror is found to be 0.756 times the size of the object. If the distance from the mirror to the screen on which the image appears is 0.764 m , what is the focal length of the mirror?

    2. Relevant equations

    (a) 1 /do + 1/di = 1/f

    (b) image height / object height=m = - di/do

    (c) - object height / image height = do / di

    3. The attempt at a solution
    m= 0.756 = -hi / ho

    so to use equation "c"

    i inverted --- > -1/0.756
    then set it euqal to rest of the equation so --> -1/.756 = do / .764
    do= -1.01058 m

    then i used equation "a"

    (1/-1.01058) + (1/.764) = 1/f and solved for f

    Answer was Wrong. Please tell me what I need to do. Thank you!
  2. jcsd
  3. Apr 2, 2009 #2


    User Avatar
    Homework Helper

    Re: concave mirror!!!

    I got the answer 0.435 m. Is it correct? If so check your sign convention.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook