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प्रश्न
What is the function of iris and the muscles connected to the lens in human eye?
उत्तर
- Function of Iris: The iris is a muscular diaphragm that controls the size of the pupil, which, in turn, controls the amount of light entering the eye. It also gives color to the eye.
- Function of ciliary muscles: The ciliary muscles hold the eye lens in position and adjust its focal length by expanding and contracting.
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संबंधित प्रश्न
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
State whether these spectacle lenses will converge light rays or diverge light rays.
Where is the image formed in a human eye?
How does the eye adjust to take account of an increase in brightness?
Out of rods and cones m the retina of your eye:
which work in dim light?
What is the principal function of the eye-lens?
What changes the shape of lens in the eye?
Fill in the following blank with suitable word:
Most of the refraction of light rays entering the eye occurs at the outer surface of the.............
If you walk from a dark room into sunlight and back again into dark room, how would your pupils alter in size? What makes this happen?
Which parts of the eye cause rays of light to converge on the retina?
A student sitting on the last bench in the class cannot read the writing on the blackboard clearly but he can read the book lying on his desk clearly. Which of the following statement is correct about the student?
(a) The near point of his eyes has receded away.
(b) The near point of his eyes has come close to him.
(c) The far point of his eyes has receded away.
(d) The far point of his eyes has come closer to him.
How much is our field of view:
with one eye open?
Fill in the following blank with suitable word:
Having two eyes enables us to judge.................more accurately.
With reference to the functioning of the eye, answer the question that follow:
Name the cells of the retina and its respective pigments which get activated in the dark.
Correct and rewrite the statements by changing the biological term that is underlined for the statement:
The part of the eye which can be donated from a clinically dead person is the Retina.
Name the following:
The opening through which light enters the eyes.
The diagram alongside represents a certain defect of vision of the human eye.
(i) Name the defect.
(ii) Describe briefly the condition in the eye responsible for the defect.
(iii) Redraw the figure by adding a suitable lens correcting the defect. Label the parts through which light-rays pass.
(iv) What special advantage do human beings derive in having both eyes facing forward?
Choose the correct answer :
The rods and cones of a vertebrate retina function is to _________
Draw a labeled diagram of the front view of human eye.
Name the following:
The pigmented circular area seen in the eye.
Name the following:
The focal length of the lens is altered by the contraction of which type of muscles.
Give Technical Term:
The cells of the retina that are sensitive to colour.
Mention, if the following statement is True or False
Rods are responsible for vision in the dark
State the Function:
Aqueous humour
Complete the following sentence with appropriate Word
The aperture in the eye through which light enters is the:
For the normal human eye, the near point is at ___________ cm.
The image of the object in the human eye is formed on the cross screen.
Vision defect that increases distance between the lens of the eye and retina of the eye is termed as myopia.
The following figure show the change in the shape of the lens while seeing distant and nearby objects. Complete the figures by correctly labelling the diagram.
In a myopic eye, the image of the object is formed
A person cannot see distinctly objects kept beyond 2 m. This defect can be corrected by using a lens of power
Name the part of the eye which gives colour to the eyes.
Select the option with incorrect identification:
| 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 accomodation |
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.
The layer in the eye where sensory cells (rods and cones) are located ______.
The thin, transparent extension of sclerotic layer found in front of the lens is ______.
Name the following:
Two pigments of the sensory cells.
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.
