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Homework Help: A Mirror's Reversal Property

  1. Jul 21, 2004 #1
    There has been this question that has been bothering me for quite sometime. It is an assignment question I failed to answer...

    Can anyone explain to me in terms of light and the laws of reflection the reason why Mirrors reverse an image left-to-right?
  2. jcsd
  3. Jul 21, 2004 #2


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    They don't.

    When it is in front of you, it reverses front to back, not left-right. This makes your left hand look like a right hand.

    When you stand on one, it reverses top to bottom. Only when it is to your side, does it reverse left-right.

  4. Jul 21, 2004 #3


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    A mirror DOESN'T reverse anything. THAT'S why images in a mirror look peculiar. Imagine a person standing beside you stepping in front of you. In order for you to see her, she would have to turn around- i.e. reverse! Because you are used to that, when a mirror DOESN'T reverse, it looks peculiar.

    Another example: look in the mirror as you are driving- everything LOOKS reversed. That's not because the mirror has reversed anything. In order to see the same thing without the mirror, you would have to turn around- reversing yourself. Using a mirror you lose that reversal you normally have.
  5. Jul 21, 2004 #4


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    I think what Njorl means by "reverses front to back" is that the operation defined by 'reflection' takes P=(x,y,z) to P'=(x,y,-z) for a mirror along z=0.
  6. Jul 22, 2004 #5
    thanx guys.. you've helped me out ^_^
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