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-   -   Optics (https://www.askmehelpdesk.com/showthread.php?t=774476)

  • Nov 9, 2013, 03:03 AM
    ayodeji95
    Optics
    A man 2m tall whose eye level is 1.84m above the ground looks at his image in a vertical mirror. What is the minimum vertical length of the mirror if the man is able to see the whole of himself? Indicate its position accurately in a diagram.@ebaines I still don't understand.
  • Nov 9, 2013, 09:24 AM
    ebaines
    Draw a diagram with one sight line going from the man's eyes to the mirror and back to the man's feet - remembering that the angle of incidence equals the angle of reflection at the mirror - and a second from his eyes to the mirror and back to the top of his head. Note where the intersection of the sight line and mirror occurs. This will give you the height of the mirror required to see to the top of his head plus the height to see his feet.
  • Nov 9, 2013, 10:22 AM
    ayodeji95
    I still Nid to know d distance by the way d mirror Ans d man
  • Nov 9, 2013, 10:25 AM
    ayodeji95
    I still need to know the distance between the mirror and the man
  • Nov 9, 2013, 10:30 AM
    ayodeji95
    Can u Jst help me wit d steps and Ans Nid it B4 tomorrow aftanun.
  • Nov 11, 2013, 06:57 AM
    ebaines
    1 Attachment(s)
    Actually you do not need to know the distance from the man to the mirror. Try it some time: stand before a mirror and note how much of your body you can see. Then take several steps back and check again - you will find that you still see the same amount of your body.

    Look at the drawing I have attached Can you determine the relationship between h1 and d1, and between h2 and d2? Notice that there are equal triangles here, and so you can determine values of d1 and d2 from simple geometry.

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