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प्रश्न
An object is moved closer to an eye. What changes must take place in the eye in order to keep the image in sharp focus?
उत्तर
When an object is moved closer to the eye, the ciliary muscles in the eye contract. When the ciliary muscles contract, the suspensory ligaments attached to them are loosened, because of which they stop pulling the eye lens. As a result, the eye lens becomes thick and its converging power increases. The greater converging power enables the eye to focus the diverging rays from the nearby object and form a clear image on the retina.
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संबंधित प्रश्न
The optical prescription for a pair of spectacles is :
Right eye : −3.50 D
Left eye : −4.00 D
Are these lenses thinner at the middle or at the edges?
Name the part of the eye:
on which the image is formed.
Name the part of the eye:
which changes the focal length of eye-lens.
What is the:
near point of a normal human eye?
Name the part of our eyes which helps us to focus near and distant objects in quick succession.
Nocturnal animals (animals which sleep during the day and come out at night) tend to have wide pupils and lot of rods in their retinas. Suggest reasons for this.
Define the following:
Yellow spot
Draw a scientifically correct labelled diagram of a human eye and answer the questions based on it:
- Name the type of lens in the human eye.
- Name the screen at which the maximum amount of incident light is refracted?
- State the nature of the image formed of the object on the screen inside the eye.
Draw the struture of human eye and label its parts.
Chris was watching the display of fireworks in the sky.
- Trace the path of the light rays using the following terms:
Fovea, Lens, Conjunctiva, Pupil, Cornea. - Name the nerve that carries the impulse for vision to the brain.
