Rays from the sun converge at a point 15 cm in front of a concave mirror. Where should an object be placed in front of this mirror so that the size of its image is equal to the size of the object?
30 cm in front of the mirror
Since parallel beams are converging at 15 cm distance, so focal length of the mirror is 15 cm.
As we know that the object kept at the centre of curvature will produce an image of the same size as that of the object.
Radius of curvature is twice the focal length so the object should be kept at a distance of 30 cm from the pole of the mirror.