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Rays from Sun converge at a point 15 cm ...

Rays from Sun converge at a point `15 cm` in front of a concave mirror. Where should an object be placed so that size of its image is equal to the size of the object ?

A

15 cm in front of the mirror

B

30 cm in front of the mirror

C

Between 15 cm and 30 cm in front of the mirror

D

More than 30 cm in front of the mirror

Text Solution

Verified by Experts

The correct Answer is:
B
The distance of the sun is infinite as compared to the radius of curvature of concave mirror, so, light rays from sun incident parallel all the rays converge at the principal focus. So, the focal length is 15 cm.
In case of a concave mirror, the size of image and object will be same if the object is placed at 2f. Hence, in this case object must be place at 2f or `2xx15` = 30 cm.
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