If the distance of object from mirror decreases by ‘x’. Then, distance between object and image decrease by ‘2x’. Now for plane mirror, u = v ∴ Initial distance between object and image will be = 10 m According to question decrease in distance of object from mirror is 1 m. So, decrease in object and image distance will be 2 m. Therefore, new distance between object and image = 10 m – 2 m = 8 m.