A student notices a small printed sentence at the bottom of the driver’s side mirror on her car. It reads, “Objects in the mirror are closer than they appear.” Which type of mirror is this (convex, concave, or flat)? How could you confirm the shape of the mirror experimentally?
Question by OpenStax is licensed under CC BY 4.0
Final Answer

The mirror is convex.
Move the object very close, and move it gradually farther away. Observe that the image is always upright. This indicates a convex mirror.

Solution video

OpenStax College Physics for AP® Courses, Chapter 25, Problem 18 (Test Prep for AP® Courses)

OpenStax College Physics, Chapter 25, Problem 18 (AP) video thumbnail

In order to watch this solution you need to have a subscription.

Start free trial Log in
vote with a rating of votes with an average rating of .
Video Transcript
This is College Physics Answers with Shaun Dychko. The driver's side mirror on a car has a small print that says "Object's in the mirror closer than they appear" and this is a convex mirror and we can confirm that it's convex by positioning an object right in front of the mirror very close to it and then move the object gradually further away and we'll notice that at every position of this object, the image is always upright and that's only true for a convex mirror; a concave mirror has the image inverted when the object is closer to the mirror than the focal point.