Exam 4
We’ll grade it tomorrow afternoon
 The problem where you had to had to find
n for a hydrogen atom after absorbing a
photon . . . Reduce points possible by 9
points, grade out of 3 points.

Final Exam
All Finals week in the testing center
Same format as midterms but no free response
- one page of notes
- bring a calculator, scratch paper, pencils,
erasers
Final Exam
- 16 multiple choice
– 2 problems from each unit like problems on
midterms
 If I asked a question about pressure change in
isothermal, be prepared to do isovolumetric, etc.
 If I asked a question about a lens, I might ask a similar
one about a mirror, etc.
 May be similar to a free response question
– 2 problems from each midterm with different
numbers
Other Announcements

SPS Finals Review
– 6-7 in the underground lab
 Go to the bottom floor of ESC, middle of hallway
running along north of building
 Door to the right of a small staircase going up
 Open door, go all the way down the stairs
– Food at 5

Course Evaluations
– extra credit 20/1 point quiz
Rate the Tutors
If you used the physics tutorial lab
this semester, we invite you to rate the
tutors you received help from.
Rating form and photos of tutors:
http://gardner.byu.edu/tas/tutorrating.php
Requested Review

Energy of photon vs wavelength

Energy of atom with a given n
Unit 2 Review
Ideal Gas—PV=nRT—Watch units
W work done by gas vs. on gas
Adiabatic, constant V, T and P
Thermal equilibrium—Entropy
Unit 2 Review
Heat --Internal energy – degrees of freedom
1st and 2nd laws of thermodynamics
Temperature change: Q=mcT
Phase change: Q=mL
Radiation, convection, conduction
In an ideal gas, if you double the volume of
the container, while keeping the
temperature and the number of molecules
the same, the pressure in the gas
Decreases
B. Stays the same
C. Increases
A.
Suppose we have two jars of gas, one of helium
and one of oxygen. If both jars have the same
volume, and the two gases are at the same
pressure and temperature, which jar contains the
greatest number of molecules?
A. Jar of helium
B. Jar of oxygen
C. Both jars contain the same number.
Consider both gases to obey the ideal gas law. Also note
that the mass of an oxygen atom is greater than the mass
of a helium atom.
Cwater=4186 J/kg oC
Cgold=129 J/kg oC
Which heats up faster using the same heat source?
1 kg water
B. 1 kg gold
C. They both heat up at the same rate.
A.
Q  mcT
Q is energy transferred
Put 100g Al at 100o C into 500g water at 20o
C. What is the final T?
cAl=900 J/kg oC
cH2O=4186 J/kg oC
What will the final T be?
100o
B. 97o
C. 20o
D. 23o
E. 60o
A.
The first law of thermodynamics
∆Eint = Q + W
Change of internal energy = heat
put into system + work done on
system
The internal energy of an ideal gas depends
only on the temperature of the gas.
True or False: Given two different
objects, the one with the higher
temperature contains more heat.
(a) T
(b) F
The path shown below is adiabatic (Q = 0).
The change in internal energy of the gas is
P
V
Positive
B. Negative
C. zero
A.
In the path shown, the change in internal
energy of the gas is
P
Negative
B. Positive
C. Zero
A.
V
In the path shown below, the gas returns to
its original state. The net change in internal
energy is
P
Positive
B. negative
C. zero
A.
V
In the path shown below, the heat
Q put into the gas is
(a) negative.
(b) zero.
(c) positive.
P
V
In the path shown below, the gas returns to
its original state. The heat put into the gas
is
P
V
Positive
B. negative
C. zero
A.
One of the P-V curves below is for an
isothermal process. The other is for
an adiabatic process. Which is
adiabatic?
P
A
B
V
Two gases in separate containers have equal
volumes, equal numbers of molecules, and the
same internal energy Eint. However, one gas is
monatomic and the other is diatomic. The
pressure of the diatomic gas is
A. Less than that of the monatomic gas.
B. The same of that of the monatomic gas.
C. Greater than that of the monatomic gas.
The second law of thermodynamics says for
a heat engine
You can’t get more work energy out than you
consume in heat
B. You can’t get out all of the heat energy as work
C. You will get out more work energy than you
consume in heat
A.
Did you know, for example, that the two greatest
intellectual achievements of the last century, the
general theory of relativity and quantum mechanics,
are in some points in conflict with each other. They
cannot both be right in every detail. These are not
my words, but the words of Stephen Hawking, the
great British physicist. Yet, scientists rely on both of
these theories every day to advance scientific
knowledge, knowing that some day the differences
will be understood, reconciled, and corrected.
So it is with the gospel and our testimonies, yours
and mine. This is not to suggest that the gospel is
imperfect, but our understanding of it sometimes
is. Like the scientist that uses relativity and
quantum mechanics, we do not discard the gospel
or our testimony because not every piece fits
today.
Richard G. Hinckley
Prophetic Priorities
BYU Devotional, May 15, 2007
Unit 3 Review

Ray approximation

Reflection

Refraction-Snell’s Law
Unit 3 Review

Mirrors-equations and drawing principle rays

Lenses-equations and drawing principle rays
Unit 3 Review

Real and virtual images

Magnification
Unit 3 Review

Camera

Glasses

Magnifying glass
Unit 3 Review

Microscope

Telescope
Unit 3 Review

Double and Single slit interference

Diffraction Grating
Unit 3 Review

Thin film interference

Telescope (eye, radar dish, etc.) resolution
An object is placed in front of a concave mirror.
Depending on the position of the object, the image
formed may occur
A.
B.
C.
D.
Behind the mirror and be
real
In front of the mirror
and be virtual.
In front of the mirror
and be upright
None of the above
Which of the following best describes the
image for a thin diverging lens that forms
whenever the magnitude of the object distance
is less than that of the lens' focal length?
Real and upright
B. Real and inverted
C. Virtual and upright
D. Virtual and inverted
A.
You are designing eyeglasses for someone whose near point
is 60 cm. What focal length lens should you prescribe so
that an object can be clearly seen when placed at 25 cm in
front of the eye?
A.
B.
C.
D.
E.
-15 cm
-18 cm
18 cm
43 cm
60 cm
Group question: a flat glass microscope slide (n=1.5)
with parallel sides in air is illuminated with green
light (λ=520 nm). Light reflects off both surfaces.
What do you see in top view (what is the combined
light reflected off the slide)?
A.
B.
C.
D.
All dark
All bright
Dark and bright fringes
Not enough information is
given
Discussion question: An oil film on water reflects different colors
more or less brightly owing to interference, depending on
the film thickness. All the colors reflect brightly where the
film is thinnest. (thin compared to visible wavelengths,
approximately zero but enough to have a reflected ray off
the oil and the water), From this information, we can tell
that the index of refraction of the oil is
Less than that of water.
B. The same as that of water.
C. Greater than that of water.
A.
Discussion question: An interference pattern is formed on a
screen by shining a planar wave on a double-slit
arrangement (left). If we cover one slit with a glass plate
(right), the phases of the two emerging waves will be
different because the wavelength is shorter in glass than in
air. If the phase difference is 180°, how is the interference
pattern, shown left, altered?
A.
B.
C.
D.
E.
The pattern vanishes
The bright spots lie closer together.
The bright spots are farther apart.
There are no changes.
Bright and dark spots are
interchanged
Unit 4 Review
Relativity
Postulates of Special Relativity
Time Dilation
Length Contraction
Unit 4 Review
Relativity
Lorentz Transformations
Adding velocities
Relativistic energy and momentum
After your friend drives past you in a car at
a speed of 0.6 c, they turn on their
headlights, and in their reference frame
they measure the light traveling away
from them at 2.9979x108 m/s. How fast
will YOU measure the light traveling?
(a) 2.9979x108 m/s
(b) Less than 2.9979x108 m/s
(c) More than 2.9979x108 m/s
Your friend waves at you while they drive
past you in a car. Who measures the
proper time for how long they waved at
you?
(a) You
(b) Your friend
(c) None of the above
Your friend waves at you while they drive
past you in a car. Who measures the
longer time for how long they waved at
you?
(a) You
(b) Your friend
Your friend waves at you while they drive
past you in a car. Who measures the
proper length of their car?
(a) You
(b) Your friend
(c) None of the above
Your friend drives past you in a car traveling
at a velocity of 0.8 c. Your enemy travels
past you in the opposite direction at a
speed of 0.7 c. What velocity will your
friend measure your enemy to be moving
at?
(a) 0.1 c
(b) c
(c) 1.5 c
(d) None of the above
Your friend drives past you in a car traveling
at a velocity u. The car has a mass m.
What is the momentum of the car?
(a) mv
(b) mc
(c) γmc
(d) γmv
(e) None of the above
Your friend drives past you in a car traveling
at a velocity u. The car has a mass m.
What is the kinetic energy of the car?
(a)
(b)
(c)
(d)
(1/2) mv2
mc2
γmc2
None of the above
Unit 4 Review
Quantized Light - photons
Energy of a photon
Photoelectric effect
Compton effect
Unit 4 Review
Quantum mechanics
de Broglie wavelength
uncertainty
Bohr atom
Which photon has more energy – a red
photon with a wavelength of 650 nm or a
blue photon with a wavelength of 450
nm?
(a) The red one
(b) The blue one
(c) They have the same energy
(d) Not enough information is given
A photon with an energy of 2.1 eV hits a
metal with a work function of 1.8 eV.
What’s the kinetic energy of the electron
kicked off by this interaction?
(a) 0.3 eV
(b) Not 0.3 eV
(c) What was the question?
(d) Not enough information is given
A photon with a wavelength of 0.2 nm
scatters off of an electron. The scattered
photon comes out at an angle of 10
degrees from the direction that the
incoming photon was traveling. What
equation gives me the change in
wavelength of the photon.
ℎ
𝜆 − 𝜆0 =
(1 − cos 𝜃)
𝑚𝑒 𝑐
′
Which has a smaller de Broglie wavelength,
an electron traveling at 10 m/s or a car
traveling at 10 m/s?
(a) The electron
(b) The car
(c) An undisclosed third party
What is the uncertainty in velocity of a
goldfish of mass m trapped in a bowl with
linear dimensions l ?
What is the wavelength of the photon
emitted when the electron in a hydrogen
atom drops from the n=4 to the n=2
energy level?
Unit 4 Review
Nuclear Physics
Notation, atomic number, mass number
Half life
Unit 4 Review
Nuclear Physics
Decay types
Fission
Fusion