An object is 12 cm in front of a plane mirror. The mirror is moved 4 cm towards the stationary object. The image position shifts by:
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Question

An object is 12 cm in front of a plane mirror. The mirror is moved 4 cm towards the stationary object. The image position shifts by:

G1 Physics · Accepted Answer

For a plane mirror, the image is as far behind the mirror as the object is in front. If the mirror moves by 4 cm towards the fixed object, the object-mirror distance decreases by 4 cm. The image position relative to the fixed object changes by twice the mirror displacement: image shift = 2×4 = 8 cm The image shifts towards the new mirror position. Hence option D follows.