Question

In order to obtain double-sized erect image of a 3 cm pencil with a concave mirror of focal length 10 cm, at what distance should the pencil be placed in front of the mirror? *

a) 10 cm

b) 15 cm

C)5 cm

d)20 cm

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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. The size of the image will be larger than object. Ray diagram is attached as image to the question.