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प्रश्न
Answer briefly:
How do you perceive the colour of an object?
उत्तर
Photoreceptors are cells that are sensitive to light. They are of two types – rods and cones. These are present in the retina. Cones help in distinguishing colours. There are three types of cone cells – those responding to green light, those responding to blue light, and those responding to red light. These cells are stimulated by different lights, from different sources. The combinations of the signals generated help us see the different colours.
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संबंधित प्रश्न
Write the function of the following part of the human eye:- iris
Compare the following: Choroid and retina
Explain the mechanism of vision.
State whether the following statement is true or false:
The image formed on our retina is upside-down
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Explain why, we cannot see our seats first when we enter a darkened cinema hall from bright light but gradually they become visible.
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(a) cornea
(b) ciliary muscles
(c) optic nerve
(d) iris
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.
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(a) Animals having two eyes on the opposite sides of their head.
(b) Animals having two eyes at the front of their head.
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Which of these persons can donate eyes?
Five persons A, B, C, D and E have diabetes, leukaemia, asthma, meningitis and hepatitis, respectively.
Which of these persons cannot donate eyes?
Name the following:
The part of the eye responsible for its shape.
Define the following:
Blind spot
What are the functions of tears?
What is meant by power of accommodation of the eye?
For a normal human eye the near point is at _______.
Assertion: Blind spot is a small area of the retina which is insensitive to light where the optic nerve leaves the eye.
Reason: There are no rods or cones present at the junction of the optic nerve and retina in the eye.
In human eye the part which allows light to enter into the eye is ______.
Assertion (A): Rods and Cones are photoreceptors in the sclera of eyeball.
Reason (R): Rods are sensitive to dim light.
