Summer 2009
DEPARTMENT OF PHYSICS
August 3, 2009
PHYSICS 2C: Fluids, Thermodynamics, Waves &
Optics
INSTRUCTOR
Charles Hicks, Mayer Hall 2651
jchicks@ cox.net
Office Hr: 40 minutes following each class or by
appointment.
COURSE COORDINATOR
Patti Hey, 118 Urey Addition, x2-1468
plhey@physics.ucsd.edu
TEACHING ASSISTANT
Kitran Colwell, Mayer Hall 2702
kcolwell@physics.ucsd.edu
Office Hrs: Wed and Thurs. 11:00-12:00AM
COURSE SCHEDULE
Lectures:
M-Th
8:00-9:20 AM
WLH 2111
Quiz:
Fr
8:00-9:20 AM
WLH 2111
Problem Session:
Th
10:00-10:50 AM
WLH 2111
Discussion:
W
10:00-10:50 AM
WLH 2111
TEXT
Wolfson & Pasachoff, Physics for Scientists and Engineers, Volume III, 3rd Edition
(special UCSD custom bind paperback edition, ISBN 0536-17026-6)
COURSE DESCRIPTION
Physics 2C is the third quarter of a four-quarter introductory physics sequence. The
course is aimed at students majoring in science and engineering (e.g. chemistry,
molecular biology, computer science, mathematics). It is a continuation of Physics 2B
covering fluid mechanics, thermodynamics, wave motion and sound, Maxwell’s
equations and electromagnetic waves, geometric optics, interference and diffraction. The
course will closely follow the textbook by Wolfson and Pasachoff, Chapters 16-22 and
34-37. Lecture notes, Problem plus Quiz solutions, and Course Announcements will be
online at http://physics.ucsd.edu/students/courses/summer2009/
Prerequisites:
Physics 2A and 2B; Math 21C and concurrent enrollment in Math 21D, or equivalent.
Knowledge of calculus will be assumed.
Problem and Discussion Sessions:
A one hour long problem session will be held weekly on Thursdays from 10:00-10:50 in
Warren Lecture Hall 2111. It will focus on problem solving under the guidance of the
TA. Your active participation is strongly encouraged. Note that some of the exam
questions will come directly from the problem assignments. Additionally there will be a
weekly discussion session on Wednesdays from 10:00-10:50 in Warren Lecture Hall
2111. These can be very helpful in clearly up conceptual issues and your attendance is
again strongly encouraged.
Homework Assignments.
Problems will be assigned twice per week as per the attached schedule. Additionally two
problems will be assigned to be turned in and graded. These problems are due by the end
of class on Friday. Each of the problems to be graded will be worth 10 points so that the
total maximum score from these problems will be 100 points. This total will be worth an
additional quiz score. To understand the material, however, you must practice solving all
of the problems, and it is very important for you to work on your own, and only consult
the solutions as a check or if you are stuck. Studying in groups may be valuable, but it
can not completely substitute working on your own, since the first step in solving a
problem is often also the most challenging one. Problems given on the weekly quizzes
will often resemble the homework problems. The textbook contains numerous worked
sample problems, and a number of problems and questions at the end of the chapter.
Solutions of many of those can be found in the Students’ Solution Manual (on reserve in
the library.) Please, remember that learning physics is about understanding why a
solution works, rather than about getting the correct numerical result.
QUIZZES
Closed-book quizzes will be given on Friday every week. A 3x5 cheat card will be
allowed. Additionally, the necessary equations will be written on the blackboard or
in the quiz. Any requests for formulas will usually be honored and written on the
board for everyone. Solutions and scores will be posted on the web. Your overall quiz
grade will be computed from your highest 4 scores which includes the 4 quizzes + the
total score on the problems that are turned in. This total will count 2/3 toward your final
grade. Note that if you turn in the assigned problems, one quiz can be missed without
penalty. The quizzes will be composed of multiple choice problems. You will have to
provide your own scantron card, form No. X-101864-PAR. They are available at the
bookstore and the general store co-op for about $0.15 ea. You will need a No. 2 pencil to
fill in the scantron. Bring a scantron form and a pencil or you'll receive no credit for
the quiz.
1. You may use a calculator (but not a laptop) during the quiz. You may wish to bring
some blank scratch paper as well as you almost certainly need it!
2. At the first quiz, you will be assigned a code number. This code number will be used
to identify your answer sheet for each quiz. Write your code number, your name,
the course number and quarter on the Scantron form. Code number errors
(missing or incorrect code number) will be penalized with a deduction from the
quiz score.
3. Any appeal of quiz grades should be made in writing to the TA, within one week of
the posting of that quiz. You must provide an explanation for why you are appealing
the grade (be specific).
4. There will be no make-up quizzes for any reason what-so-ever! If you anticipate
missing more than one quiz due to unavoidable circumstances, you must discuss this
with the instructor beforehand and should seriously consider dropping the
course.
FINAL EXAM
The final will be a closed-book exam and cover the whole course material, and it will
be composed of multiple choice problems, just like the quizzes. So, you should bring a
Scantron form with you. You may use a calculator (but not a laptop) during the final. You
may also bring a single 8 1/2” x 11” sheet of paper of formulae and notes handwritten
on the both sides. (Printed cheat-sheets are not allowed!) You may wish to bring some
blank scratch paper as well as you will likely need it. The final will be given on
Saturday, September 5th, from 3:00 PM to 6:00 PM, location TBA. Your student I.D.
is required to bring it.
COURSE GRADE:
Quizzes
Final Exam
2/3 (best 400 out of 500)
1/3
ACADEMIC DISHONESTY
Please read "UCSD Policy on Integrity of Scholarship" in the UCSD General Catalog.
These rules will be rigorously enforced. Any confirmed case of cheating will result in an
“F” grade in Physics 2C and referral to the appropriate dean for disciplinary action. For
the purposes of this class, cheating includes submitting another person’s work as your
own, copying from another student on Quizzes or the Final Exam (or knowingly allowing
another student to copy from you), and use of unauthorized materials during a Quiz or
Final Exam. Cheating also includes attempts to manipulate grades unfairly and
intentionally misusing code numbers.
ADD/DROP PROCEDURE
Use WebReg, http://summersession.ucsd.edu/students-reg.shtml, to add/change/drop,
drop from waitlists. No add/drop cards will be signed by the instructor or TA.
WHOM TO SEE
Contact: Sharmila Poddar or Richard Hsu E-mail: Spoddar@physics.ucsd.edu or
Rhsu@physics.ucsd.edu; 115 Urey Hall Addition, Physics Dept. Student Affairs Office,
if you have any trouble using WebReg to add/change/drop, drop from waitlists.
The Teaching Assistant; if you have questions relating to problem solving methods or to
grades received.
The Instructor; if you have basic questions about the subject matter, or if you have
administrative problems.
Schedule of classes, homework and quizzes.
Week
Chapters from Wolfson and Pasachoff
Quiz date
Homework Questions and Problems.
I
Aug
3
18 Fluid Motion
19 Temperature and Heat
Aug 7
II
Aug
10
20 Thermal Behavior of Matter
21 First law of Thermodynamics
Aug 14
III
Aug
17
22 The Second Law of Thermodynamics
16 Wave Motion
Aug 21
IV
Aug
24
17 Sound and other Wave Phenomena
34 Electromagnetic Waves
35 Reflection and Refraction
Aug 28
V
Aug
31
36 Image formation
37 Interference and Diffraction
Q. Ch 18: 5, 6, 9, 11, 12, 16, 17, 18, 22, 23
P. Ch 18: 9, 13, 15, 25, 29, 35, 38, 47, 48, 51, 57
Q. Ch 19: 1, 2, 3, 7, 10, 12, 14, 15, 19, 22;
P. Ch 19: 1, 5, 12, 21, 22, 25, 35, 40, 51, 53, 55, 64
Q. Ch 20: 2, 5, 7, 9, 12, 16, 17, 19, 23, 28, 31
P. Ch 20: 5, 10, 11, 15, 17, 21, 30, 47, 49, 57, 59
Q. Ch 21: 1, 4, 8, 9, 11, 12, 13, 16, 19, 20, 22
P. Ch 21: 3, 7, 9, 11, 17, 21, 23, 25, 31, 39, 43, 45
Q. Ch 22: 2, 4, 9, 10, 16, 17, 18, 19
P. Ch 22: 1, 2, 8, 11, 13, 15, 17, 23, 25, 39, 45, 53
Q. Ch 16: 1, 3, 7, 10, 11, 13, 14, 17, 18, 21, 23
P. Ch 16: 1, 9, 13, 15, 23, 35, 39, 43, 47, 49, 50, 52
Q. Ch 17: 2, 3, 5, 7, 8, 9, 11, 12, 15, 16, 17, 18
P. Ch 17: 8, 11, 15, 17, 27, 37, 39, 45, 53, 56, 57, 63
Q. Ch 34: 9, 10, 11, 14, 17, 18, 21
P. Ch 34: 13, 17, 21, 29, 33, 35, 37
Q. Ch 35: 2, 5, 6, 7, 8, 11, 14, 19, 21
P. Ch 35: 1, 2, 5, 9, 13, 15, 25, 27, 33, 35, 37, 41, 43,
55
Q. Ch 36: 1, 4, 6, 7, 9, 10, 11, 13, 15
P. Ch 36: 3, 5, 9, 15, 19, 25, 29, 37, 43, 49, 51, 61
Q. Ch 37: 1, 3, 4, 5, 6, 8, 9, 10, 11, 13, 14, 16
P. Ch 37: 1, 3, 9, 11, 15, 17, 25, 31, 36, 41, 51, 55,
57, 61
Problems to be turned in and graded:
Due Date
August 7
August 14
August 21
August 28
Problems
1. Chapter 18, problem 68.
2. Radioactive sphere. A radioactive sphere of radius R₁ generates heat at a uniform rate H.
It is surrounded by an insulating concentric spherical shell of heat conductivity k and
outer radius R₂. (a) Find the rate of heat flow, H, if the temperatures at the inside and
outside radius of the insulating sphere are T₁ and T₂ respectively with T₁>T₂. (b) Find
the thermal gradient dT/dr inside the insulator and comment on the radial dependence
and sign of dT/dr.
3. (a) Chapter 20, problem 72, (b) Show that the average speed satisfies <v>/vrms=(8/3π)1/2
for a molecule in an ideal gas, (c) Given that the velocity of sound in an ideal gas is
vs=( γ P/r)1/2 where γ is a constant depending on nature of the molecules in the gas, show
for an ideal gas that vs/vrms =(γ/3)1/2.
4. Given the average molecular weight of Earth's atmosphere is m=29.0 and γ=1.4, show
that speed of sound in the Earth's atmosphere at T=20°C is vs =343m/s. (b) Using the
ideal gas law and dP/dz =−ρg, show that P(z)=P₀e-z/zo where z0=RT/mmolg. (c) Assuming
that atmospheric pressure at sea level is P₀=1atm=14.7lbs/in² and the average
temperature is T=14°C determine the atmospheric pressure in Denver (z=1600m) in
lbs/in². Compare your result to the actual average barometric pressure of 12.1lbs/in².
5. Chapter 21, problem 68.
6. (a) Consider the adiabatic free expansion of n₁ moles of an ideal gas at pressure P1i from
a volume V1i into a volume V=V1i+V2i in which the volume V2i contains n₂ moles of
another ideal gas at pressure P2i < P1i. Find the change in entropy due to this free
expansion in terms of the initial and final pressures and the number of moles of each gas.
Hint, consider two reversible isothermal processes. In the first process the gas in volume
V2i is compressed isothermally into a volume V2f consistent with the final equilibrium
pressure, Pf. Then consider an isothermal expansion of the gas in volume V1i into a
volume V1f consistent with this same final equilibrium pressure. (b) From the result
obtained in part (a) show that the change in entropy reduces to the change in entropy for
an adiabatic free expansion of an ideal gas from volume Vi into a final volume Vf . Also
show from the result obtained in part (a) that Δs=0 if the initial pressure of the gas in the
second chamber is equal to the initial pressure of the gas in the first chamber.
7. On a relatively hot day, 30°C, a student measures two successive resonances above a
well at 52Hz and 60Hz. Determine (a) the order of the resonances and (b) the depth of
the well.
8. An isosceles triangular prism with apex angle F has an index of refraction n. Show that
the condition on the incident angle q1 so that light can emerge from the other side is:
sin q1>sqrt(n2-1)sin F-cos F.
September 4
9. The focal length for the thin lens in the figure is f=F1=F2=5cm. The mirror has a radius of
curvature R=8cm. The lens and mirror are placed 20cm apart and an object is placed 8cm
to the left of the lens. (a) Determine the position of the final image as seen by eye in the
figure. (b) Determine the magnification of the image and whether or not it is inverted or
upright.
10. Slit 1 of a double slit is wider than slit 2 so that the light from slit 1 has an electric field
3E0 times versus E0 from slit 2. Show that the intensity on the screen is given by the
expression S ~ (1+3cos2φ/2) where φ=(2π/λ)dsinθ with dsinθ being the difference in
path length from the slits to the screen.