Instructor: Dr. Bruce Law, CW
327, Tel: 532-1618.
REVIEW QUESTIONS OF Home Work 17
R28.5. The angle of incidence is equal to
the angle of reflection.
R28.6. The image is
the same distance behind the mirror as the object is in front of the mirror.
critical angle corresponds to that angle of incidence (when going from a more
dense medium (eg. water) to a less dense medium (eg. air)) where the refracted (or transmitted beam) travels
along the surface. NOTE: for angles of incidence above the critical angle there
is NO refracted beam.
R28.27. The light “bends”
in an optical fiber because the angle of incidence is always above the critical
angle and therefore ALL of the light is reflected (and none of it is refracted
or transmitted through the surface of the fiber).
EXCERISES OF Home Work 17
E28.7. In the “nighttime”
position the glare from the headlights, which comes from the silvered BACK
surface of the mirror, is reflected above the head of the person (see diagram
in book on right). The driver can still see the cars behind him because he is
looking at the much weaker reflection from the wedged non-silvered FRONT
surface of the mirror.
E28.25. (THIS QUESTION WILL NOT BE IN ANY
EXAM OR TEST – IT IS FOR YOUR ENTERTAINMENT!) You would aim the spear
below the fish. Light from the fish, as it passes through the water/air surface,
is refracted AWAY from the normal into your eyes. Your brain thinks that light
travels in a straight line – however because of the refraction of light
at the water/air surface the fish is in reality below the position that you actually
see it. To actually hit the fish with a laser beam you would point the laser
beam directly at the fish because (as with light from the fish) the laser beam
is refracted in passing through the air-water surface.
PROBLEMS OF Home Work 17
P28.4. You approach the mirror at 2m/s and your
image approaches the mirror at 2m/s. Therefore, you and your image approach
each other at 4m/s.