Question

David is observing his image in a plane mirror. The distance between the mirror and his image is $4\text{m}$. If he moves $1\text{m}$ towards the mirror, then the distance between David and his image will be

• A. $3\text{m}$
• B. $5\text{m}$
• C. $6\text{m}$
• D. $8\text{m}$

Answer 1

The correct option is C $6\text{m}$

Initial seperation between David and his image, $x=4\text{m}+4\text{m}=8\text{m}$

As David moves $1\text{m}$ towards the mirror, the image also moves $1\text{m}$ towards the mirror.

So, the new seperation between David and his image will be $x^{\prime }=8\text{m}-2\text{m}=6\text{m}$.

Hence, option (c) is the correct answer.


$\text{Point to remember :- Object distance from a plane mirror is equal to image distance}\text{from the plane mirror}$