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A convex lens made of glass forms a sharp image on the screen for a particular position of an object with respect to the lens. A human eye lens is also a convex lens but it can form sharp images on the retina of eye for different positions of the objects. Explain, why?
How is a normal eye able to see distinctly distant as well as nearer objects? What is the distance of distinct vision?
What is short-sightedness? How can this defect be corrected?
Why do we have two eyes instead of one eye?
What is presbyopia? State the cause of Presbyopia. How is presbyopia of a person be corrected?
For two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below:
(a) Both A and R are true, and R is correct explanation of the assertion.
(b) Both A and R are true, but R is not the correct explanation of the assertion.
(c) A is true, but R is false.
(d) A is false, but R is true.
Assertion: There is no dispersion of light refracted through a rectangular glass slab.
Reason: Dispersion of light is the phenomenon of splitting of a beam of white light into its constituents’ colours.
For two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below:
(a) Both A and R are true, and R is correct explanation of the assertion.
(b) Both A and R are true, but R is not the correct explanation of the assertion.
(c) A is true, but R is false.
(d) A is false, but R is true.
Assertion: A beam of white light gives a spectrum on passing through a hollow prism.
Reason: Speed of light outside the prism is different as the speed of light inside the prism.
What is long-sightedness? How can this defect be corrected?
When we enter a dim-lit room from a bright light, we are not able to see the object in the room for some time.
Explain, why?
Or
Why does it take some time to see objects in a cinema hall when we just enter the hall from bright sun light? Explain.