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: Curved Mirrors (concave)

  1. May 14, 2006 #1
    how can you tell when the image will become real or virtual in a concave mirror, the distance?..i'm not sure

    thanks in advance

    *edit*
    oh i think i know..is it the magnification, if the magnification is more than 1 then that means its virtual since it would be upright and a bigger image

    is that right?
     
    Last edited: May 14, 2006
  2. jcsd
  3. May 14, 2006 #2

    Hootenanny

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    This is correct;
    Using the standar equation for a mirror;

    [tex]\frac{1}{d_{O}} + \frac{1}{d_{i}} = \frac{1}{f}[/tex]

    When [itex]d_{i}[/itex] is positive, the image is real; if it is negative the image is virtual. [itex]d_{i}[/itex] is the horizontal displacement of the image from the centre of the mirror. [itex]d_{O}[/itex] is the horizontal displacement of the object from the centre of the mirror and [itex]f[/itex] is the focal length of the mirror (which is positive for a concave mirror).

    It is possible it have a real image that is larger than the object. What is the definition of a real and virtual image?

    More information is available here;
    http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/mirray.html#c3
     
  4. May 14, 2006 #3
    Actually if the magnification is +ve , the image is virtual.
    -ve->real
    (As per new Cartesian sign convention)
     
  5. May 14, 2006 #4

    Hootenanny

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    I agree, that's why I said above
    I did forget to mention however, that the image would be inverted.

    ~H
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook




Loading...
Similar Threads for Curved Mirrors concave Date
Optics Problem (Curved Mirror + Lens) Dec 18, 2012
Curved Mirror mathematics? Jul 17, 2010
Curved mirror identification & magnification question Jun 5, 2010
Help with curved mirrors! Oct 18, 2009
Curved mirror calculations. Feb 23, 2008