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: 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


    User Avatar
    Science Advisor

    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


    User Avatar
    Science Advisor

    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


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    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 ^_^
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook