Chapter 16
Waves-I
Part 2
2/04/13
Phys 272
1
16.6: Wave Speed on a Stretched String
The speed of a wave along a stretched ideal string depends only on the tension
and linear density of the string and not on the fre
Fluids - 3
1/30/13
Phys 272
2
Review: i-clicker:
Imagine holding two iden9cal bricks under water. Brick A is just beneath
the surface of the water, while brick B is at a greater depth. The force
needed to hol
Chapter 17
Sound Waves
2/06/13
Phys 272
1
Review i-clicker:
When a wire under tension oscillates in its third harmonic mode, how many
wavelengths are observed?
a) 1/3
b) 1/2
c) 2/3
d) 3/2
Chapter 22
Electric Fields
22.2 The Electric Field:
The electric field, E, consists of a
distribution of vectors in the region around
a charged object, such as a charged rod.
A positive test charge q0, placed at the point will
experience an electrostatic
Grades
Exam 1: 15%, Exam 2: 15%, Final: 25%,
HW: 15%, Quiz: 15%, i-clicker:15%
Exam I: Monday, Feb 25 during 3:25-4:30pm in PHY-LH
Exam II: Monday, April 8 during 3:25-4:30pm in PHY-LH
Final Exam: Wednesday, May 15 during 12:00-3:00pm in PHY-LH
1st HW due
Example Double-Slit Interference:
Intensity maxima at:
Minima at:
dsin = m
1
dsin = (m + )
2
On a screen at a distance D from slits and (D>d) how far is rst-order
Maximum from central bright fringe (i.e., what is y)?
E
Chapter 32
Maxwells Equations;
Magnetism of Matter
4/15/13
Phys 272
2
32.2: Gauss Law for Magnetic Particles:
The law asserts that the net magnetic flux B through
any closed Gaussian surface is zero. Here B is the magnetic field.
Fig 32-2 A bar magnet is
Induction Part 2
4/01/13
Phys 272
4
Eddy Currents: I induced in a piece of bulk metal.
Metal disk rolling through magnet.
Rolling in: increasing outward
flux. CW induced current
Force F=ILB towards left
Rolling out: decreasing outward
flux. CCW induced cu
Velocity Selector
+
+
+
+
+
+
+
+
Make a beam of charged particles
enter a region of crossed E and B
fields.
q
v
X
B
E
_
_
_
_
_
_
_
_
E is down and B is into paper so
that E perpendicular to B.
FE is down and FB is up.
If beam is not deflected, FE=FB.
So
Chapter 33
EM Waves
Part 2
4/17/13
Phys 272
3
Maxwells Rainbow:
In the wavelength scale in the figure, (and similarly the corresponding frequency scale), each scale marker
represents a change in wavelength (and correspondingly in frequency) by a factor of
3/6/13
Phys 272
1
Colloquium Today just after class!
3/6/13
Phys 272
2
Chapter 25
Capacitance
3/6/13
Phys 272
3
Reminder: Long thick conducting plate
Long thick conducting plate with surface
charge density of ! in C/m2.
Left: E =0 inside conductor, "=0 th
Magnetic Fields and Currents
Part 2
4/01/13
Phys 272
3
Ex: Two wires carry currents I and 3I as shown.
Where is B=0?
4/01/13
Phys 272
4
Ex: Two wires carry currents I and 3I as shown.
Where is B=0?
4/01/13
Phys 272
5
Ex: Equal and opposite currents as sho
Exam 2 is on April 8th Chapters 23-27
Make-up for people who has 3 or more exams on the 8th
is on April 4th from 12:10 to 1 pm in Serin 401 e-mail me if you
need to take the make-up and didnt receive a confirmation email this
afternoon.
3/25/13
Phys 272
i-clicker:
We charge a capacitor, so it stores some energy. Then we increase
the plate separation. What is the new energy of the capacitor?
a) Same as before
b) Less than before
c) More than before
3/6/13
Phys 272
3
i-clicker:
We charge a capacitor, so it
Chapter 27
Circuits Part 2
Toaster
Household Electrical Wiring
Is household wiring in series like this?
Fridge
Microwave
NO! Why Not?
But with parallel connection we might draw too much current!
Too much current might melt insulation. P=I2R
Fuses and circ
33.8: Chromatic Dispersion and Rainbow:
Dispersion means index n varies a bit, depending on lambda (i.e, color)
Sun must be behind us.
Sunlight and reflected light must make an angle of ~41 degrees.
Rainbow has violet at bottom, red on top
2nd rainbow: 2
Graphical methods for lenses
34.7: Thin Lenses: Converging
f>0, thicker in middle than at ends.
1) Ray parallel to axis hits lens, then goes through far focal point.
2) Ray through center of lens is undeviated
3) Ray trough near focal point hits lens then
22.8: A Point Charge in an Electric Field : Motion in an electric field
Given a charge q in an electric field E, how will the charge move?
Charge will feel force F=qE, then F=ma, so a =F/m=qE/m!
Example:
E=10 N/c and v0x=5X105 m/s
y Find the vertical defl
Chapter 21
Electric Charge
2/11/13
Phys 272
1
Review i-clicker:
Three observers, A,B, and C are listening to a moving source of
sound. The diagram below shows the location of the wavecrests of
the moving source with respect to the three
observers. Which o
Schrodingers Equation
Fitting the distribution to a Gaussian gives a mean of 9.5
and width of 2.5. The untted mean is 10 and the RMS is
2.7. There were 22 A's and 36 B's out of 80 total students.
Randomly picking answers would yield 3.2 correct
answers on
Particles and Waves
Reduced Mass: consider two particles of mass m1 and
m2 and velocities v1 and v2
The center of mass velocity is
m1 v 1 + m2 v 2
V=
m1 + m2
Notice how V lies on the line joining v1 and v2?
v2
V
vand Waves
1
Physics 273 Particles
2
Now, l
Radioactivity
Many nuclides are unstable. There are three (common)
types of radioactive decay:
Alpha decay: a Helium nucleus is emitted
Beta decay: an electron or positron is emitted
Gamma decay: a photon is emitted
We will consider the physics of each of
Nuclear Forces
Initial evidence for the nucleus came from Rutherford
scattering (1911).
Fired alpha particles (two protons + two neutrons) at a
gold foil.
Found that, every once in a while, a proton would
scatter back as if it had hit a hard target!
Physi
The Bohr Model of Hydrogen
Exam Details
The exam will be held Wednesday, October 3rd from
1:452:50pm.
I will be away that entire week. In anticipation of
this, I will hold an extra set of ofce hours on Friday,
September 28 from 24pm. Please plan ahead!
Particle Nature of Light
Exam Details
The exam will be held Wednesday, October 3rd from
1:452:50pm.
I will be away that entire week. In anticipation of
this.
I will hold an extra set of ofce hours on Friday,
September 28 from 24pm. Please plan ahead!
If y
Quantization of Electromagnetic
Radiation
Society of Physics Students - First
Meeting!
Thursday, September 20 - 8:00 PM, PLH
For our rst meeting of the semester, we will introduce everyone to the Society of Physics Students, discuss our plans for the
seme
Fun With Paradoxes
A classic Relativity paradox: Two ships of equal proper
lengths approach each other along antiparallel paths
A
B
When the nose of A reaches the tail of B, then A will
re a torpedo from its tail perpendicular to the direction
of motion.
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