(question by Henry Greenside, Duke Physics)
Consider three identical square planar mirrors that are gluedtogether to form three adjacent sides of a cube meeting at acorner, with the mirrored sides all facing towards each other. Showthat these mirrors act as a universal reflector that sends lightback to its source: any light beam entering this arrangement ofmirrors will leave parallel and opposite to its originaldirection.
If you look into such a corner reflector, what kind of image willyou see of your face?
Note: Such corner reflectors were left on the surface of the moonby Apollo astronauts and were used in ranging experiments, in whichlaser beams from an observatory on Earth were bounced off thesurface of the Moon and returned to the observatory, with the timeof transit being measured. This enabled the distance from the Earthto the Moon to be measured with high accuracy which has been usefulin testing the theory of general relativity and also forinvestigating the geology and origin of the Moon.
(question by Henry Greenside, Duke Physics)
Consider three identical square planar mirrors that are gluedtogether to form three adjacent sides of a cube meeting at acorner, with the mirrored sides all facing towards each other. Showthat these mirrors act as a universal reflector that sends lightback to its source: any light beam entering this arrangement ofmirrors will leave parallel and opposite to its originaldirection.
If you look into such a corner reflector, what kind of image willyou see of your face?
Note: Such corner reflectors were left on the surface of the moonby Apollo astronauts and were used in ranging experiments, in whichlaser beams from an observatory on Earth were bounced off thesurface of the Moon and returned to the observatory, with the timeof transit being measured. This enabled the distance from the Earthto the Moon to be measured with high accuracy which has been usefulin testing the theory of general relativity and also forinvestigating the geology and origin of the Moon.
