If the mirror moves a distance of 1 cm in the direction of the body so, the distance of the image from the first image is a)1cm b)2cm c)3cm and why

The answer is 1cm. the reason is that the distance of an image from the mirror is the same as the body from the mirror. So if  at first ,the body was 3cm  away from the mirror then the image is 3 cm from the mirror so if the mirror is moved 1 com towards the body, then the distance now is 2cm for both body and image. The distance of the image(2cm) from the first(3cm) is 1 cm I think.

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