Question

The  magnification  produce  by  the  plane  mirror  is  +1.what  does  this  mean?

Answer 1

this means that the mirror is plane mirror and it produces the image which is as same as that of an object
the image is virtual and erect and is formed behind the mirror

Answer 2

here magnification is positive it means both the object and image are erect . Since virtual image is always erect , so positive magnification indicates that the image formed by a spherical mirror is virtual .

hope it will help