A fish swims below the surface of the water at point P. An
observer at point O sees the fish at:
1) a greater depth than it really is
2) the same depth
3) a shallower depth than it really is
A fish swims below the surface of the water at point P. An
observer at point O sees the fish at:
1) a greater depth than it really is
2) the same depth
3) a shallower depth than it really is
A fish swims below the surface of the
water. Suppose an observer is looking
at the fish from point O, which is
directly above the fish.
The observer
sees the fish at:
1) a greater depth than it really is
2) the same depth
3) a shallower depth than it really is
A fish swims below the surface of the
water. Suppose an observer is looking
at the fish from point O, which is
directly above the fish.
The observer
sees the fish at:
1) a greater depth than it really is
2) the same depth
3) a shallower depth than it really is
To shoot a fish with a gun, should you aim directly at the image
that you see, slightly above the image, or slightly below it?
1) aim directly at the image
2) aim slightly above
3) aim slightly below
To shoot a fish with a gun, should you aim directly at the image
slightly above or slightly below?
1) aim directly at the image
2) aim slightly above
3) aim slightly below
You will see the fish at a position above its actual
position, so you should aim below this image.
To shoot a fish with a laser pistol, should you aim directly at the
image slightly above or slightly below?
A)
B)
C)
D)
aim directly at the image
aim slightly above
aim slightly below, about where you would aim a gun
aim even further below than you would aim with a gun
To shoot a fish with a laser pistol, should you aim directly at the
image slightly above or slightly below?
A)
B)
C)
D)
aim directly at the image
aim slightly above
aim slightly below, about where you would aim a gun
aim even further below than you would aim with a gun
The light from the laser beam will also bend when it
hits the air-water interface, so aim directly the fish.
An observer views two closely spaced lines
through an angled piece of glass. To the
observer, the lines appear:
1) shifted to the right
2) shifted to the left
3) spaced farther apart
4) spaced closer together
5) no change -- exactly as before
1 v1t
2 v2t
1
i
v1t
r
h
i
2
v2t
r
Snells’ Law
sin inc  inc vinc


sin refr  refr vrefr
We can classify materials by their “index of refraction” defined as
the ratio of
speed of light in a vacuum, c
speed of light through medium, v
c
c
i.e. n 
v
Note then that:
v
n
sin inc vinc c / ninc 1 / ninc nrefr




sin refr vrefr c / nrefr 1 / nrefr ninc
So often Snell’s Law is also written as:
reversing
the
indices!
n1sin1 = n2sin2
A ray of light is shown entering a glass prism, bending
down (toward the normal) as it enters.
As the ray re-enters the air through the opposite face of the prism
(1) it bends up.
(2) it passes through without bending.
(3) it bends further down.
A ray of light is shown entering a glass prism, bending
down (toward the normal) as it enters.
Glass-into-air:
light bends
away from normal
Air-into-glass: light
bends toward normal
As the ray re-enters the air through the opposite face of the prism
(1) it bends up.
(2) it passes through without bending.
(3) it bends further down.