PHYSICS 24: GENERAL PHYSICS

WINTER 2009

Lecture: MWF 1:00-1:50 in Broida 1640
Discussion: Fri 12:00-12:50 in Phelps 3523



ANNOUNCEMENTS

3/12: Solutions for the mirror/lens practice problems:
practice problem solutions


3/12: Since HW 7 was only 3 problems, here are a few practice problems to work on involving mirrors and lenses:
HRK Chapter 40 Exercise 39
HRK Chapter 40 Problem 3 (the wording is unclear, think of the "linear object" as an arrow which points away from the mirror)
HRK Chapter 40 Problem 10

3/11: Here are the solutions for Homework 9:
HW 9 Solutions

3/10: Here is a link to the flyer about tomorrow's "celebration of finishing E&M (the first time around)":
Pattaya show flyer
There is no extra credit for this of course, please come only if you're interested or if you just want some yummy food on my dime.

3/10: Here are the solutions for Homeworks 7 and 8 to help you study for next Thursday's exam (HW 9 coming soon):
HW 7 Solutions
HW 8 Solutions

2/24: For HW#7, Problem 1, the wording of the problem has changed so that you don't end up trying to solve a nasty differential equation. See below.

2/17: Here are the solutions for Homeworks 4-6 to help you study for Friday's midterm:
HW 4 Solutions
HW 5 Solutions
HW 6 Solutions

1/27: Here are the solutions for Homeworks 1-3 to help you study for Friday's midterm:
HW 1 Solutions
HW 2 Solutions
HW 3 Solutions

1/15: For HW#2, Chapter 34 Exercise 18, the problem statement should also mention that the rod has resistance R and that the rails have negligible resistance.

1/4: Happy New Year! Welcome to Physics 24...




COURSE INFORMATION

Lecturer: Doug Folsom ( email: )
Office: Broida 6302
Office Hours: Monday 12:00-1:00, Wednesday 12:00-1:00, 2:00-3:00

TA: Andrew Merrill ( email: )
Office: Physics Study Room (Broida 1019)
Office Hours: Monday 2:30-4:30, Thursday 3:00-4:00

Textbook:

Halliday, Resnick, and Krane Physics, 5th edition, Volume 2


Course Outline:

Physics 24 is a continuation of Physics 23. This quarter we will continue to examine electricity and magnetism (E & M). We will cover magnetic induction, AC circuits, Maxwell's equations, and optics. The lectures will supplement the textbook; we will cover some sections in a different order and introduce extra examples.


Grading:

Grades will be based on 9 homeworks and 3 exams. The final exam will be non-cumulative and similar in length to the midterm exams.

Homework: 25%
Exams: 75% ( each is worth 25% )

Homeworks will be due in the Physics 24 box in the PSR at 5pm on Mondays and returned the following Monday. Late homeworks will receive reduced scores unless prior arrangements have been made with the TA.

Course Schedule:

Lecture
Topic
HW / Exam
1/5
Magnetic Properties of Materials
1/7
Magnetic Properties of Materials
1/9
Faraday's Law and Inductance
1/12
Faraday's Law and Inductance HW 1 due
1/14
Faraday's Law and Inductance
1/16
Faraday's Law and Inductance
1/19
NO LECTURE -- Martin Luther King Day HW 2 due Tuesday 1/20 by 5 pm
1/21
AC Circuits
1/23
AC Circuits
1/26
AC Circuits HW 3 due
1/28
Maxwell's Equations
1/30
Midterm 1 Midterm 1
2/2
Maxwell's Equations HW 4 due
2/4
Maxwell's Equations
2/6
Electromagnetic waves
2/9
Electromagnetic waves HW 5 due
2/11
Electromagnetic waves
2/13
Mirrors and lenses
2/16
NO LECTURE -- Presidents' Day HW 6 due Tuesday 2/17 by 5pm
2/18
Mirrors and lenses
2/20
Midterm 2 Midterm 2
2/23
Mirrors and lenses HW 7 due
2/25
Interference and Diffraction
2/27
Interference and Diffraction
3/2
Interference and Diffraction HW 8 due
3/4
Polarization
3/6
Polarization
3/9
Intro to Special Relativity HW 9 due
3/11
Intro to Special Relativity
3/13
Final Exam Review
3/19
FINAL EXAM 4:00 - 7:00 FINAL EXAM


Homework #1

Graded:
HRK Chapter 35 Exercise 6, Problem 2 (omit part c), Problem 6

Ungraded:
HRK Chapter 34 Problems 5, 6
HRK Chapter 35 Exercise 29, Problem 1


Homework #2

Graded:
HRK Chapter 34 Exercise 18 (omit part c), Problem 14
HRK Chapter 36 Problem 11

Ungraded:
HRK Chapter 34 Exercise 16, 26
HRK Chapter 36 Exercise 9, 10


Homework #3

Graded:
HRK Chapter 36 Exercise 47, Problem 10

1. In class, we listed 3 ways to write a real oscillating function x(t):

Show that these 3 are equivalent by:
a)solving for C and &phi in terms of B1 and B2
b)solving for A1 and A2 in terms of B1 and B2
(Hint: Keep in mind A1 and A2 are complex numbers! Use Euler's Law and trig identities. )

Ungraded:
HRK Chapter 36 Exercise 31, 49
HRK Chapter 36 Problem 13 (omit part c)


Homework #4

Graded:
HRK Chapter 37 Problems 3, 7
HRK Chapter 38 Exercise 9

Ungraded:
None


Homework #5

Graded:

1. In class, we showed how to change from the integral form of Gauss' Law to the differential form. Do the same thing for Maxwell's Equation number 3. i.e. show that:

Hint: Use a tiny square loop for the loop integral. To get the full vector equation, you will have to repeat this 3 times (when you have done it once, you can just quote your earlier results).


2. In class, we used the following on the way to deriving the existence of electromagnetic waves:
Show that this equation is true by writing out all the gradients, cross products, and dot products in vector form.


3. a) Plug an arbitrary function E = E0 f( kxx + kyy + kzz + &omega t ) into the wave equation. Show that the wave equation is satisified, no matter what f is ( do not use a specific f ), as long as kx, ky, kz, and &omega are related appropriately.
Hint: Call the function f(u) and use the chain rule.

b) Show that the equation c = &lambda f is satisfied. How do &lambda and f relate to kx, ky, kz, and &omega ?


Ungraded:
1. Show that the curl of the gradient of any scalar field is zero.

2. Show that the divergence of the curl of any vector field is zero.

Homework #6

Graded:
HRK Chapter 38 Exercise 16, Problem 11
HRK Chapter 39 Problem 12

Ungraded:
HRK Chapter 38 Problem 9
HRK Chapter 39 Exercise 25
HRK Chapter 39 Problem 3


Homework #7

Graded:
1. Prove that the ideal shape for a convex mirror is a parabola.
Hint: Place the tip of the mirror at the origin of a 2-D coordinate system. Pick a focal point a distance f away. Visualize light rays pointing away from the focal point and use these rays to find an equation relating y, x, and dy/dx of the mirror. Finally, plug in using a general parabola equation y = Cx2 and show that you get a true statement.

2. Prove these equations using a convex lens as an example:
1) 1/o + 1/i = 1/f
2) m = -i / o
Assume all light rays have small angles of incidence.

HRK Chapter 40 Exercise 30


Homework #8

Graded:
HRK Chapter 40 Problem 7
HRK Chapter 41 Exercise 19
1. Consider a spherical mirror of radius R. Using a Taylor expansion to second order, show that the spherical mirror approximates a parabolic mirror and find the approximate focal length in terms of R.

Ungraded:
HRK Chapter 40 Problem 12
HRK Chapter 41 Exercises 2, 21


Homework #9

Graded:
HRK Chapter 41 Exercise 29, Problem 3
HRK Chapter 42 Problem 7 (omit part c)

Ungraded:
HRK Chapter 41 Problem 7
HRK Chapter 42 Exercise 29