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Ray Optics and Optical Instruments — Physics STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 SciencePhysicsRay Optics and Optical Instruments1 Mark
MCQ

 A normal eye is not able to see objects closer than 25cm because:

  • A
    The focal length of the eye is 25cm.
  • B
    The distance of the retina from the eye-lens is 25cm.
  • C
    The eye is not able to decrease the distance between the eye-lens and the retina beyond a limit.
  • D
    The eye is not able to decrease the focal length beyond a limit.
✓

Answer

  1. The eye is not able to decrease the focal length beyond a limit.

Explanation:

The ciliary muscles adjust the focal length to form an image on the retina, but the muscles cannot be strained beyond a limit. Hence, if the object is brought too close to the eye, the focal length cannot be adjusted to form the image on the retina.

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