The outside rearview mirror of modem automobiles is marked with warning “objects in mirror are closer than they appear”. Such mirrors are

Modern automobiles use convex mirrors as outside rearview (wing) mirrors to enhance driver safety. These mirrors are curved outwards, which provides a significantly wider field of view compared to plane mirrors, allowing drivers to monitor a larger area of traffic behind them [2]. A fundamental property of convex mirrors is that they always produce virtual, erect, and diminished (smaller) images of objects [1]. Because the human brain often associates smaller image size with greater distance, objects in these mirrors seem further away than they actually are. Consequently, the safety warning "objects in mirror are closer than they appear" is engraved on them to alert drivers to this optical distortion. While concave mirrors can magnify or invert images depending on distance, convex mirrors maintain a consistent, reduced image that minimizes blind spots [4].

Sources

1. [2] Science , class X (NCERT 2025 ed.) > Chapter 9: Light – Reflection and Refraction > Uses of convex mirrors > p. 142
2. [1] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 10: Light: Mirrors and Lenses > Activity 10.3: Let us explore > p. 156
3. [4] https://en.wikipedia.org/wiki/Objects_in_mirror_are_closer_than_they_appear