Question

1.(a) It is desired to obtain an erect image of an object, using a concave mirror of focal length 20 cm.
(i) What should be the range of distance of the object from the mirror?
(ii) Will the image be bigger or smaller than the object?
(iii) Draw a ray diagram to show the image formation in this case.
(b) One half a convex lens of focal length 20 cm is covered with a black paper.
(i)Will the lens produce a complete image of the object?
(ii)Show the formation of image of an object placed at 2F1 of such covered lens with the help of a ray diagram.
(iii)How will the intensity of the image formed by half-covered lens compare with non-covered lens? ​

Answer 1

Answer:

Object distance should be less than the focal length for the formation of an erect image. Hence, the range of distance of object from the mirror should be less than 15 cm i.e. from 0 to 15 cm in the front of mirror from the pole. The nature of image so formed will be virtual and erect.

Explanation:

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