Exploration 33.1: Image in a Flat Mirror

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A bear stands in front of a plane mirror that is hanging on a wall. A point source of light is located near the mirror. You can drag this source to any location and can change the angle of its rays by click-dragging on the hotspot (position is given in meters and angle is given in degrees). Restart.

  1. At what point on the mirror must the bear look in order to see her feet? For simplicity and ease, assume the bear's eye is located at the tip of her nose.
  2. Move the bear to the position x = 1.0 m. If the bear looks at the same spot in the mirror found in (a), what will she see? Does this imply that she is able to see more, less, or the same amount of her body in the mirror when she moves away from the mirror?
  3. In terms of the bear's height, how long must the mirror be for her to see her entire body?

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Exploration authored by Melissa Dancy.

Physlets were developed at Davidson College and converted from Java to JavaScript using the SwingJS system developed at St. Olaf College.

OSP Projects:
Open Source Physics - EJS Modeling
Physlet Physics
Physlet Quantum Physics
STP Book