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प्रश्न
Define the term.
Power of accommodation of the eye.
Answer the following question.
What is meant by the power of accommodation of the eye?
उत्तर १
The ability of the eye lens to adjust its focal length, so as to clearly focus rays coming from distant as well a near objects on the retina, is called the power of accommodation of the eye.
उत्तर २
When the ciliary muscles are relaxed, the eye lens becomes thin, the focal length increases, and the distant objects are clearly visible to the eyes. To see the nearby objects clearly, the ciliary muscles contract making the eye lens thicker. Thus, the focal length of the eye lens decreases and the nearby objects become visible to the eyes. Hence, the human eye lens is able to adjust its focal length to view both distant and nearby objects on the retina. This ability is called the power of accommodation of the eyes.
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संबंधित प्रश्न
Draw a labelled sketch of the human eye.
A person got his eyes tested by an optician. The prescription for the spectacle lenses to be made reads :
Left eye : +2.50 D
Right eye : +2.00 D
Which lens bends the light rays more strongly?
Fill in the following blank with suitable word:
To bring light from a distant object to a focus on the retina of the eye, the convex eye-lens needs to be made..........
What change is made in the eye to enable it to focus on objects situated at different distances? Illustrate your answer with the help of diagrams.
What happens to the eye when you enter a darkened cinema hall from bright sunshine? Give reason for your answer.
How does the convex eye-lens differ from the ordinary convex lens made of glass?
Name the cells on the retina of an eye which are sensitive to (i) bright light (ii) dim light (iii) sensation of colour.
Explain clearly why, a person who has lost the sight of one eye is at a disadvantage compared with the normal person who has two good eyes.
Having two eyes gives a person:
(a) deeper field of view
(b) coloured field of view
(c) rear field of view
(d) wider field of view
Explain the Term: Accommodation in the eye
Name the capacity of the eye lens to change its focal length as per need.
Write scientific reason.
The movie cannot be enjoyed if seat of a viewer is too close to the screen in the cinema.
A tiny mirror M is fixed on a piece of cardboard placed on a table. The cardboard is illuminated by light from a bulb. The position of eye with respect to position of bulb is shown in the figure as A, B, C and D. In which position mirror will be visible?
 |
 |
 |
 |
| (A) | (B) | (C) | (D) |
What is ‘white of the eye’?
Match the following:
| Column - I | Column - II |
| 1. Retina | a. Path way of light |
| 2. Pupil | b. Far point comes closer |
| 3. Ciliary muscles | c. near point moves away |
| 4. Myopia | d. Screen of the eye |
| 5. Hypermetropia | e. Power of accommodation |
Arrange and rewrite the term in group in correct order to be in a logical sequence, beginning with the term that is underlined:
Pupil, Aqueous humour, Retina, Vitreous humour.
Assertion (A): Rods and Cones are photoreceptors in the sclera of eyeball.
Reason (R): Rods are sensitive to dim light.
Name the following:
Place of no vision in the retina of the eye.
Name the following:
The layer of the wall of the eye-ball that corresponds to the black lining of the box of a camera
With reference to human eye answer the question that follow:
Name the part of the eye associated with the regulation of the size of pupil.
