Obtain the position, nature and size of an image formed by a plane mirror from the formula of magnification.

In case of plane mirror the magnification is + 1;

Positive value of magnification indicates that image formed by plane mirror is erect.

Also, Magnification =

⇒ Image height = Object height.

Therefore, Image formed by plane mirror is of the same size as of the object.

Magnification =

⇒ v = - u;

This shows that image formed by plane mirror is at same distance as the object but behind the mirror means image is virtual.

Thus, Image formed by plane mirror is virtual, erect and same as size of the object.