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प्रश्न
Differentiate between members of the following pair with reference to what is asked in the bracket.
Rods and cones (sensitivity).
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उत्तर
Rods: They are sensitive to dim light but do not respond to colour.
Cones: They are sensitive to bright light and are responsible for colour vision.
संबंधित प्रश्न
About 45 lac people in the developing countries are suffering from corneal blindness. About 30 lac children below the age of 12 years suffering from this defect can be cured by replacing the defective cornea with the cornea of a donated eye. How and why can students of your age involve themselves to create awareness about this fact among people?
What is short-sightedness? State the two causes of short-sightedness (or myopia). With the help of ray diagrams, show:
(i) the eye-defect short-sightedness.
(ii) correction of short-sightedness by using a lens.
Given below is a diagram depicting a defect of the human eye? Study the same and answer the question that follow:
Give two possible reasons for this defect of the eye in human beings.
Have a look at the posture of this woman who is reading a book and answer the questions which follow:
What are the two conditions shown in sections A and B of the eye as applicable to her?
Complete the following sentence with appropriate word :
An inability to focus on nearby objects due to loss of elasticity of the lens with age is called Iris.
In Myopia the human eye _______.
Given below is a diagram showing a defect of vision. Name the defect of vision and draw an accurately labelled diagram to correct this defect.
Myopia and hypermetropia can be corrected by:
When do we consider a person to be myopic or hypermetropic? Explain using diagrams how the defects associated with myopic and hypermetropic eye can be corrected?
Name the following:
Two kinds of accomodations.
