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प्रश्न
Give the main function of the following:
Retina
उत्तर
Retina - It prevents the reflection of light.
APPEARS IN
संबंधित प्रश्न
Differentiate between: Rods and cones
The region of the vertebrate eye, where the optic nerve passes out of the retina, is called the
(a) fovea
(b) iris
(c) blind spot
(d) optic chaisma
The term " accommodation" as applied to the eye, refers to its ability to:
(a) control the light intensity falling on the retina
(b) erect the inverted image formed on the retina
(c) vary the focal length of the lens
(d) vary the distance between the lens and retina
A man driving a car can read a distant road sign clearly but finds difficulty in reading the odometer on the dashboard of the car. Which of the following statement is correct about this man?
(a) The near point of his eyes has receded away.
(b) The near point of his eyes has come closer to him.
(c) The far point of his eyes has receded away.
(d) The far point of his eyes has come closer to him.
Which of the following have a wider field of view?
(a) Animals having two eyes on the opposite sides of their head.
(b) Animals having two eyes at the front of their head.
Fill in the following blank with suitable word:
Having two eyes gives a ................field of view.
Five persons A, B, C, D and E have diabetes, leukaemia, asthma, meningitis and hepatitis, respectively.
Which of these persons cannot donate eyes?
The animals called predators have:
(a) both the eyes on the sides
(b) one eye on the side and one at the front
(c) one eye on the front and one at the back
(d) both the eyes at the front
With reference to the functioning of the eye, answer the question that follow:
What is the shape of the lens during near vision?
Differentiate between:
Yellow spot and Blind spot.
Give Technical Term:
The nutritive layer of the eye which also presents reflection of light.
Mention, if the following statement is True or False
Cones are the receptor cells in the retina of the eye sensitive to dim light.
State the Location of:
Lacrimal gland
Shylesh is a school-going kid studying standard VIII. He is crazy about playing video games on mobile phones. After a couple of months, his eyes turned red and he felt severe pain in his eyes. His science teacher enquired about this and advised his parents to take him to an eye doctor.
- How does excessive usage of mobile phone affect our eyes?
- What are the values shown by the teacher?
A person cannot see distinctly objects kept beyond 2 m. This defect can be corrected by using a lens of power
Given below is a diagram depicting a defect of the human eye. Answer the questions that follow:
- Give the scientific term for the defect.
- Mention one possible reason for the defect.
- What type of lens can be used to correct the defect?
With neat, labeled diagram describe the structure of retina of eye.
Explain the role of the part of human eye responsible for power of accommodation of human 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 accomadation |
Name the following:
Place of best vision in the retina of the eye.
