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Periscope reflection, but it seems backwards

  1. Apr 4, 2013 #1
    Screen Shot 2013-04-04 at 8.55.28 PM.png

    Screen Shot 2013-04-04 at 8.55.32 PM.png

    This is the question and the answer choices. I thought it would be mirror one creates E and mirror 2 creates F, but It's not.... help?
     

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  3. Apr 4, 2013 #2
    Then I thought the answer might be C and G, but that's also incorrect, I'm just not sure what to do!
     
  4. Apr 5, 2013 #3

    PeterO

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    Extend the mirrors 1, so that you can find a point perpendicularly behind the mirror, and the same distance behind as well - as always happens with a flat mirror.

    Now extend mirror 2 and repeat the above step for the final image position.
     
  5. Apr 5, 2013 #4

    CWatters

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    Perhaps remember that mirrors don't magnify an image so the image can't appear closer than the distance a light ray takes from the object to the eye via the mirrors.
     
  6. Apr 5, 2013 #5
    Then I would think B would be the image from 1, but then there is no image from 2... I mean D is perpendicular, but it is further away then the distance from the object to the original mirror
     
  7. Apr 5, 2013 #6

    haruspex

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    As PeterO says, extend mirror 1 (in this case, up and to the right). If the object is at O and the image is at point X then you should find that the mirror perpendicularly bisects OX. That is not true of OB.
     
  8. Apr 6, 2013 #7

    PeterO

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    You got B by extending the line from the object past the end of the existing mirror 1. That line is not perpendicular to the mirror.

    I said extend mirror 1 - especially up to the right - then draw a line from the object that forms a right angle with the mirror.

    Images in plane mirrors are DIRECTLY behind the mirror - so the line joining an object and and image is always perpendicular to the mirror.
     
  9. Apr 6, 2013 #8

    CWatters

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    heatherro92 - Try this experiment. Go to the bathroom and stand facing the mirror. Turn 45 degrees to the right. Does the image in the mirror stay in position A or move to position B ?
     

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