The word “AMBULANCE” is painted in reverse lettering on the front of an ambulance so…
PHYSICS · Single correct · AP · Physics 2: Algebra-based · Geometric Optics · Geometric Optics
Problem
The word “AMBULANCE” is painted in reverse lettering on the front of an ambulance so that it appears normal to drivers looking in their rear-view mirrors. Which of the following best explains why the mirror seems to reverse left and right but not top and bottom?
(a) A plane mirror actually flips the image in both directions, but we only notice the left–right change because people commonly turn around horizontally, not vertically.
(b) A plane mirror reverses the direction perpendicular to its surface; our brains interpret this front-back reversal as a left-right interchange.
(c) A plane mirror rotates every light ray 180∘ about a vertical axis, so only the horizontal orientation of objects is flipped.
(d) Because our two eyes are separated horizontally but not vertically, the brain interprets the exchanged viewpoints as a left–right swap, leaving the vertical orientation unchanged.