Page 1 - Lesson note - introduction
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SAI INTERNATIONAL SCHOOL

                                                      PHYSICS

                                                      CLASS X

                              Chapter:HUMANEYE AND COLURFULWORLD

                                                    MODULE-34

               HUMAN EYE:
               The Human Eye It is a natural optical instrument which is used to see the objects by
               human beings. It acts like a camera, enable us to capture the colourful picture of the
               surroundings.An inverted, real image on light sensitive is formed on the Retina





























               The Various Parts of Eye and their Functions

               1.Sclerotic.  It  has  a  tough  and  opaque  white  covering,  called  sclerotic  which
               protects and holds the eyeball.

               2. Cornea. It is the transparent membrane on the front portion of the eyeball through
               which light enters the eye.
               3.  Choroid.  It  is a black  membrane  below  the  sclerotic.  It  absorbs  stray  light  and
               avoids any blurring of image due to multiple reflections in the eyeball.
               4. Cornea: It is a thin membrane through which light enters. It forms the transparent
               bulge on the front of eyeball. Most of the refraction occurs at the outer surface of the
               cornea.
               5. Eyeball: it is a convex lens, approximately spherical in shape, with a diameter of
               about 2.3 cm. It can alter its curvature with help of ciliary muscles.

               6. Iris: It is a dark muscular diaphragm that controls the size of pupil.It is behind the
               cornea.it helps in accommodation of light by changing the size of the pupil.





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