Refraction and Snell's Law

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Webquiz 4 Geometric Optics
Spherical mirrors Sections 26.3
26.4 Spherical Lenses Sections 26.6 26.7
and the assigned problems from those sections
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The focusing of a parallel beam of light to a
focus
is reversible
3
3 easy to trace lines can help locate the image
formed by a lens
p
f
f
q
q
M
p
With the magnification,
-
4
1
2
3
f
f / 2
4
5
The ray entering this diverging lens, parallel
to its axis, exits the other side following
which ray?
5
The divergence by a concave lens should be
reversible as well!
6
1
2
3
f
f / 2
4
Which ray entering the diverging lens exits the
other side parallel to its axis?
5
7
3 easy to trace lines can help locate the image
formed by a lens
p
f
q
f
q
M
p
With the magnification still,
-
8
f
p
q
1 f
1 p
1 q
1 q
1 f
1 p

-


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When viewing objects by eye, which variable(s)
of the lens equation must always remain fixed?

1. the focal length, f
2. the object distance, p
3. the image distance, q

(4)both f and p (5)both f and q (6)both p and q
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For everyone there is a NEAR POINT, the closest
position you can focus on
f
Any closer, the lens cannot accommodate. The eye
strains to hold f this small.
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ho
q
p
The retinal image size must be proportional to

1. the focal length, f of the lens
2. the object distance, p
3. the image distance, q

(4)the object size, ho (5)both p and q (6)both p
and ho
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(No Transcript)
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Some answers
2
Directed away from the focus on far side.
2
Directed toward the focus on near side.
(3) the image distance, q
The size of the human eye is fixed, but its lens
is flexible!
(4) the object size, ho
The size of the projected image, does also depend
on p, but notice That is an inverse proportion!
(The greater p, the smaller the image size)