Question

A girl standing in front of a vertical plane mirror, is able to see herself only upto her knees. She can see the lower part of her legs, if :

• A. she moves towards the mirror
• B. she moves away from the mirror
• C. she bends down
• D. she stands on a stool

Answer 1

Answer: (B)

she moves away from the mirror

Answer is B.
For plane mirrors, the image distance is the same as the object distance (di =-do). The only way to modify the image distance is to modify the object distance.
Therefore, for girl to see the lower part of her legs, she has to move away from the mirror.