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Homework Help: A small postage stamp is placed in front of a concave mirror

  1. Jul 24, 2010 #1
    Problem: A small postage stamp is placed in front of a concave mirror (radius=R), such that the image distance equals the object distance. (a) in terms of R, what is the object distance (b) what is the magnification of the mirror (c) state whether the image is upright or inverted relative to the object.

    Any help would be appreciated! thank u!
  2. jcsd
  3. Jul 24, 2010 #2


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    Please follow the rules of this forum and use the template when you seek help with homework. Show us the relevant equations and tell us what you tried and what you think about the problem. We just don't give answers away.
  4. Jul 24, 2010 #3
    first of all what type of image are you talking about. is it real or virtual?
    if it is a real image:
    (a) do you know where the image lies if the object is at centre of curvature? aren't image and object at the same distance from the pole of mirror. if you exactly know what 'R' is, then you must be able to guess this one. i am not directly telling you the answer. just try it.
    (b) magnification can be calculated in two ways: 1. -v/u and h of image/h of object. you simply know that image distance(v) = object distance(u). let both of them be x. now can you calculate the magnification?
    (c) come on man. real images are always inverted. you know where image is formed when object is at C. it's so easy.
  5. Jul 28, 2010 #4
    I'm not asking for answers. I don't want straight up answers because that won't help me. The only reason I did not put down any relevant equations is because I have no idea where to even begin. Sorry if I broke the rules. So far no one has helped me with this problem and the only thing that anybody has told me is how stupid I am and how I'm not able to see the answer because apparently it's so "easy." I'm just going to my professor on this one. Thanks for nothing.
  6. Jul 30, 2010 #5
    hey i have helped you out in my previous post atoreta88. if you still have problem then post it.
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