1 2 1 2
1 7 8

: .. Geometrical Optics

  1. #1

    Jul 2011
    -
    932

    .. Geometrical Optics


    Reflection and Mirrors
    . .

    300 / visible region



    geometrical optics physical optics.

    .

  2. #2

    Jul 2011
    -
    932

    : .. Geometrical Optics


    Reflection of light

    :
    Reflection: Image formation by mirrors

    . 90% .



    Reflection Law
    angle of incidence qi . angle of reflection qr . .


    qi = qr




    Image formation by plane (flat) mirror
    :



    virtual image .

    plane (flat) mirror :
    upright
    ( )
    virtual
    do di.

  3. #3

    Jul 2011
    -
    932

    : .. Geometrical Optics


    Image formation by spherical mirror
    ɡ convex mirror concave mirror.
    convex mirror concave mirror .i


    Focal length of spherical mirror
    concave mirror focus point F A focal length f.



    principal axis ǡ center of curvature C raduis of curvature r

    . f r.



    B F. CB r ( ) CB B CBF CF FB FB FA FA f CA 2FA

    r = 2f

    r ( ).

  4. #4

    Jul 2011
    -
    932

    : .. Geometrical Optics



    (1)
    :
    (1) ( ).
    (2) ( ).
    (3) C ( ).
    I .

    .
    (2)
    .
    (3)
    f r .
    (4)
    .
    (5)
    f ɡ .



    convex mirror. f C :


    convex mirror




    convex mirror

  5. #5

    Jul 2011
    -
    932

    : .. Geometrical Optics

    Mirror equation
    .

    do di f.


    do do :
    A .




    ABV DCV



    ABF D'VF .
    do .



    Mirror equation

    f = focal length (m)
    do = distance from mirror to object (m)
    di= distance from mirror to image (m)
    Magnification
    m hi ho .


    hi/ho di/do



    . :


    hi = height of the image (m)
    ho = height of object (m)
    m = magnification (how many times bigger or smaller

  6. #6

    Jul 2011
    -
    932

    : .. Geometrical Optics

    Sign convention for mirrors
    do di real virtual upright inverted :

    do+ real objectdo- virtual objectdi+ real imagedi- virtual image

    f r
    r & f+ concave mirrorr & f- convex mirror

    M
    M+ uprightM- inverted


    Example 1
    A 1.5 cm high diamond ring is placed 20 cm from a concave mirror whose radius of curvature is 30 cm. Determine (a) the position of the image, and (b) its size.

    Solution
    (a)



    f=r/2

    1/di di

    di

    (b)


    hi = m ho = -3 x 1.5 = -4.5cm
    Example 2
    A 1cm high object is placed 10cm from a concave mirror whose raduis of curvature is 30cm. (a) Draw a ray diagram to locate the position of the image. (b) Determine the position of the image and the magnification analytically.

    Solution
    (a)


    .

    (b)





    .



    Example 3
    A convex rearview car mirror has a radius of curvature of 40 cm. Determine the location of the image and its magnification for an object 10m from the mirror.

    Solution
    :


    40/2 f=r/2

    f=r/2=-40/2 =-20cm









    19.6cm .



    .
    Example 4
    A convex mirror has a radius of 20 cm. An object is placed 30 cm in front of the mirror. Determine where the image will appear.

    Since the radius is 20 cm (which is the distance from the mirror to the centre), and since the focal point is half ways in between and negative for a convex mirror,
    f = -10 cm.


    Since di is negative, it appears behind the mirror as a virtual image.
    Example 5
    For the same situation from Example 4, determine how tall the image is if the object is 5.0cm tall. Also determine the magnification.


  7. #7

    Jul 2011
    -
    14,553

    : .. Geometrical Optics




1 2 1 2

: 1 (0 1 )

  1. +
    -
    : 4
    : 17-05-2016, 08:53 AM
  2. : 1
    : 19-11-2013, 09:24 PM
  3. : 1
    : 19-11-2013, 09:22 PM
  4. : 1
    : 19-11-2013, 09:22 PM
  5. : 1
    : 02-11-2013, 07:14 PM

: 0