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Science & Technology General Science
Q.

1. Which of the following statement(s) in the context of ‘Human Eye’ is/are NOT correct?

1. Most of the refraction of the light rays entering the eye occurs at the outer surface of the crystalline lens.

2. Iris is a dark muscular diaphragm that controls the size of the pupil. 

3. Pupil regulates and controls the amount of light entering the eye. 

4. Retina is a delicate membrane having enormous number of light-sensitive cells.

Select the correct answer using codes given below:
Explanation:

 ANSWER: (A) 

  • The human eye is like a camera. The eyeball is approximately spherical in shape with a diameter of about 2.3 cm. Its lens system forms an image on a light-sensitive screen called the retina. 
  • Light enters the eye through a thin membrane called the cornea. It forms the transparent bulge on the front surface of the eyeball. Most of the refraction for the light rays entering the eye occurs at the outer surface of the cornea. 
  • The crystalline lens merely provides the finer adjustment of focal length required to focus objects at different distances on the retina. (Thus, Statement 1 is not correct)
  • We find a structure called iris behind the cornea. Iris is a dark muscular diaphragm that controls the size of the pupil. (Thus, Statement 2 is correct)
  • The pupil regulates and controls the amount of light entering the eye. (Thus, Statement 3 is correct)
  • The eye lens forms an inverted real image of the object on the retina. The retina is a delicate membrane having enormous number of light-sensitive cells. (Thus, Statement 4 is correct)

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