Convex mirrors are used in vehicles for rear view due to their wide field of view. And the convex mirror forms a virtual, erect and diminished image of the object. Therefore, magnification (m) produced by a rear view mirror fitted in vehicles is less than one i.e., m < +1 because
Magnification (m) = \(\frac{Image\,height}{object\,height}\)
And image size is less than the object size.