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Question
Object at 2F1 of a convex lens : Image at 2F2 : : Object at F1 : _______
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Solution
Object at 2F1 of a convex lens : Image at 2F2 : : Object at F1 : Image at infinity
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RELATED QUESTIONS
To determine the approximate focal length of the given convex lens by focussing a distant object (say, a sign board), you try to focus the image of the object on a screen. The image you obtain on the screen is always
(a) erect and laterally inverted
(b) erect and diminished
(c) inverted and diminished
(d) virtual, inverted and diminished
One-half of a convex lens is covered with a black paper. Will this lens produce a complete image of the object? Verify your answer experimentally. Explain your observations.
A student places a candle flame at a distance of about 60 cm from a convex lens of focal length 10 cm and focuses the image of the flame on a screen. After that he gradually moves the flame towards the lens and each time focuses the image on the screen.
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(b) How does the size of the image change?
(c) How does the intensity of the image change as the flame moves towards the lens?
(d) Approximately for what distance between the flame and the lens, the image formed on the screen is inverted and of the same size?
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Fill in the following blank with suitable word:
Parallel rays of light are refracted by a convex lens to a point called the ........
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hypermetropia
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v. Suggest a way to increase the efficiency of this microscope.
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