Rays from the Sun converge at a point 15 cm in front of a concave mirror. To get an image equal in size to the object, the object should be placed
Amore than 30 cm in front
B30 cm in front of the mirror
Cbetween 15 and 30 cm
D15 cm in front of the mirror
Answer & Solution
Correct answer: B. 30 cm in front of the mirror
Sun's rays converge at the focus, so $f=15$ cm; centre of curvature $R=2f=30$ cm. An object at C ($=2f$) gives a real image of equal size at C. So place it 30 cm in front.
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