Download Test Review 3

Physics 251 Test Review 3
(12th edition)
Test 3 covers Chapters 32-36 of the text. Review the following text sections.
- optical sign conventions (see web document)
- electromagnetic waves (Ch. 32)
see example 32.1 (fields, sinusoidal wave)
see example 32.7 (standing wave)
- reflection and refraction (Ch. 33)
see example 33.3 (reflected ray)
total internal reflection (33.4)
see example 33.5 (polarization)
section 33.7 (Huygen’s principle)
- geometric optics and instruments (Ch. 34)
example 34-6 (spherical mirrors)
example 34-8 (lens maker’s equation)
examples 34-9, 34-10 (spherical lenses)
- express the object distance in terms of the focal length
q = fp/(p-f)
when p = 5f, q => 5f2/(4f) = (5/4)f
- change the focal length in mirror/lens equations to test derived equations
q = fp/(p-f)
when f => 2f, q => 2fp/(p-2f)
when f => f/2, q => (fp/2)/(p-f/2)
- interference (Ch. 35)
- diffraction (Ch. 36)
Copyright 2008, John R. Newport, Ph.D.
1
Problem 1
NOTE: Show answer below, attach calculations.
a.)
For the converging lens data shown below, calculate the focal length. Be sure to
include proper units. (Attach separate calculations, but show the answer here.) Include
proper units for all numerical results! List results on the page below, but attach separate
calculations.
(Warning:
Be careful of optical sign conventions!)
R1
= 2.0 cm.
R2
= 1.0 cm.
n
= 1.5 (use 3/2!)
f=
__________________________________________________
b.)
If an object is placed at a distance 3f from the lens, what is the image distance?
o=
__________________________________________________
c.)
What is the magnification for the conditions cited in part b.)? Describe the image.
m=
__________________________________________________
image is (circle):
- real or virtual
- upright or inverted
- enlarged or diminished
d.)
If an object is placed at a distance f/3 from the lens, what is the image distance?
sI =
__________________________________________________
e.)
What is the magnification for the conditions cited in part d.)? Describe the image.
m=
__________________________________________________
image is (circle):
- real or virtual
- upright or inverted
- enlarged or diminished
Copyright 2008, John R. Newport, Ph.D.
2
Problem 2
A person is sipping a cola in a glass. A straw extends from the lower edge to the upper
edge (see diagram). When the person looks peers into the glass so that the refracted
image is aligned (dashed line). The person then measures the distances shown.
NOTE: Show answer below, attach calculations.
h
a.)
L
L0
What is the angle of incidence? (algebraic equation)
b.)
I = ____________________________________
What is the angle of refraction? (algebraic equation)
R = ____________________________________
c.)
These angles must be measured with respect to the
____________________________________
d.)
What is the index of refraction of the cola for the following data?
h = 4L0
L = 3L0/4
n = ____________________________________
Copyright 2008, John R. Newport, Ph.D.
3
Problem 3
NOTE: Show answer below, attach calculations.
a.)
The key principle underlying interference is
_______________________________________.
b.)
Interference offers evidence for
_______________________________________.
c.)
What happens to light rays when they undergo diffraction?
_______________________________________.
Copyright 2008, John R. Newport, Ph.D.
4
d.)
An electromagnetic wave is split into two beams and then recombined as shown
below. The first reflect wave (from the first surface) is R1 and the second is R2.
detector
LASER
R1
R2
glass
D
L0
Is there a phase shift  of at surface 1?
Is there a phase shift  of at surface 2?
Yes
Yes
The optical path length difference between
R1 and R2 is:
______________________
The condition for a bright spot at the first
surface is:
_______________________
Copyright 2008, John R. Newport, Ph.D.
5
/ No
/ No
(circle)
(circle)