mehta (snm425) Homework 4 erskine (58715) This printout should have 15 questions. Multiplechoice questions may continue on the next column or page nd all choices before answering. 001 10.0 points A charge Q is spread uniformly along the circumference of
Shie, Gary Homework 18 Due: Oct 15 2004, 4:00 am Inst: Turner This printout should have 12 questions. Multiplechoice questions may continue on the next column or page nd all choices before answering. The due time is Central time. 001 (part 1 of 2) 10 po
mehta (snm425) Homework 1 erskine (58715) This printout should have 21 questions. Multiplechoice questions may continue on the next column or page nd all choices before answering. 001 (part 1 of 3) 10.0 points For 599 nm light, calculate the critical an
E & M  Basic Physical Concepts
Electric force and electric eld
Electric force between 2 point charges: F  = k 1r2 2 k = 8.987551787 109 N m2 /C2 1 12 C2 /N m2 0 = 4 k = 8.854187817 10 qp = qe = 1.60217733 (49) 1019 C mp = 1.672623 (10) 1027 kg me = 9.1
Electric Potential Difference in a
Uniform Field
Electric potential electric potential energy per unit charge
U electric
U electric
= qV, V =
q
=
=
+
=
. , . , .
What happens to if it were a negative charge
going from bottom to top?
Nothing tes
Version 001 Third midterm niu (57625)
This printout should have 29 questions.
Multiplechoice questions may continue on
the next column or page find all choices
before answering.
001 4.0 points
Three very long wires are strung parallel to
each other as s
Plancks Solution
Max Planck correctly predicted the wavelength distribution of the
radiated energy,
2 hc 2
R( , T ) = 5 hc / kT
1)
(e
c the speed of light
k Boltzmanns Constant
from thermodynamics
h = 6.63 1034 Js Plancks constant
Molecules can only vib
Phy302L Course Organization
John Yeazell, jyeazell@austin.utexas.edu
Syllabus
First Homework Available on Quest.
Optional TA sessions will start next week.
Lab sessions will begin Wed. Jan. 22nd
Todays Class: Electric Charge and Electric
Force
What will
MIDTERM 1
Friday 2/21 , 2 PM
In Class
Bring pencils, calculators (memory cleared)
One 8.5 x 11 handwritten formula
sheet (both sides)
Magnetic Force on Charge
r
r r
Fmagnetic = qv B
Electron charge =
The magnetic force on a moving electron is in the oppo
Midterm 3, Wed. 4/30
All homeworks since last Midterm
(Reflection & Refraction, Wave Optics,
and Quantum Atomic Nuclear)
Exercise
What determines what element an atom is?
A.
B.
C.
D.
E.
The number of electrons
The number of protons
The number of neutrons
Extra Credit
The grade for Extra Credit Midterm 1 is
added to the semester average.
If you get a 100% on it, it is worth 2pts. A
75% is worth 1.5 pts., etc.
Due this Wednesday 2/24/14 at 11PM
A Long Straight Wire
0
LI
B=
4 x x 2 + ( L / 2 )2
r
r = x, y
Homework Problem
In a Youngs doubleslit experiment using 163 nm light, a thin
piece of plexiglass of refractive index 1.6 covers one of the slits.
If the center point on the screen is a dark spot instead of a bright
spot, what is the minimum thickness of
A homework problem
Symbol
Lens Radii
(location of C)
Front
Back
,

+
= ( 1)
What is the focal length? How does it change if the lens if
flipped over?
Interference and Diffraction
17th Century
Optics takes off:
1621: Refraction, W. Snell
1664: Interfere
Midterm 3, Wed. 4/30
All homeworks since last Midterm
(Reflection & Refraction, Wave
Optics, and Quantum Atomic
Nuclear)
Generating power from Nuclear Fission.
Safety and Environmental Concerns
Disposal of radioactive waste (spent fuel rods, etc.)
Catastr
Circularly polarized light
fast
slow
More than one lens?
Real image of first lens becomes the
object for the second lens
object
2
5
Assume both lenses have focal length of and object is 2 in
front of the 1st lens. Where is the first image?
If the second l
Faradays Law
Lenzs rule
Induced current is in the direction needed to produce an induced
magnetic field that tries to stop the original change in the magnetic
field.
1
2
i
1  2
Magnet moving into loop
When the magnet is moving,
the induced current in the
Waves
wavelength: distance between crests (meters)
T period: the time between crests passing fixed point (s)
v speed: the distance one crest moves in a second (m/s)
f frequency: the number of crests passing fixed point in one
second (1/s or Hz)
angular
Optional TA Sessions Start Next Week
6PM, 7PM, and 8PM, Thursdays in WEL 2.256
Undergrad TA: Austin King,
skkarkx2@aol.com
The Coulomb Force Law
1
=
=
4
0 = permittivity constant
r
+
+
2
F21
Force on 2 by 1
1
Force repulsive (+)
r
+

F21
2
1
Force at
Resistors in Circuits
There are two basic ways of arranging resistors in a circuit
(series and parallel)
Many Resistors in Series
Equivalent resistance, REQ =R1 + R2+ R3+ RN
Many Resistors in Parallel
=
+
+
+ +
Concept Question: Series Connection
Two resi
MIDTERM 1
Friday 2/21, 2PM
PAI 4.42
Bring pencils, calculators (memory cleared)
One 8.5 x 11 handwritten formula
sheet (both sides)
Circuits and Symbols
Electric circuits are portrayed with diagrams using standard
symbols, showing interconnections among
Version 025 Second midterm niu (57625)
This printout should have 26 questions.
Multiplechoice questions may continue on
the next column or page find all choices
before answering.
001 4.0 points
The two isolated parallel plate capacitors below, one with
A Homework Problem
What is the direction of the current
in the inner coil and the direction of
the Bfield due to this current?
What is the direction of the induced Bfield due to the outer coil?
What is the direction of the induced current in the outer c
Two Bulbs Near a Solenoid
Add a thick wire:
I1
Loop 1
Loop 1: emf R1 I1 R2 I 2 = 0
Loop 2: R2 I 2 = 0
I2 = 0
I2
Node:
I1 = I 2 + I 3
emf
I1 =
R1
I1 = I 3
Loop 2
I3
Exercise
Current in RL Circuit
R
t
emf battery
I (t ) =
+ be L
R
If t is zero: I (0) = 0
I
Optional TA Sessions Start THIS Week
6PM, 7PM, and 8PM, Thursdays in WEL 2.256
Undergrad TA: Austin King, skkarkx2@aol.com
Grad TA: Anindya Dey
anindya@physics.utexas.edu
Office Hours: Friday 35pm at RLM 9.318
A homework problem
Approximate a rod by a
lo
Midterm 2, Wed. 3/26
Covers homeworks: Magnetic Force and Fields,
Induced Currents, AC Circuits and EM Waves
Bring calculators, pencils, handwritten formula sheet 8.5
x 11
A homework problem
What is the energy
stored in the capacitor?
The charge in the
Electric Potential Energy of Two Particles
q2
1 q1q2
U el =
(joules)
4 0 r12
q1
Uel > 0 for two likesign charges
(repulsion)
q2
q1
Uel < 0 for two unlikesign
Charges (attraction)
Electric Potential
Electric potential electric potential energy per unit c
Midterm 2, Wed. 3/26
Covers homeworks: Magnetic Force and Fields,
Induced Currents, AC Circuits and EM Waves
Bring calculators, pencils, handwritten formula sheet 8.5
x 11
Review on Monday bring questions
Critical Angle
The critical incident angle
res
Maxwells Equations
They describe all electromagnetic fields in the universe,
outside the realm of quantum physics.
Fields Without Charges (in Vacuum)
Time varying magnetic field makes electric field
Time varying electric field makes magnetic field
Do we n
MIDTERM 1
Friday 2/21 , 2 PM
In Class
Bring pencils, calculators (memory cleared)
One 8.5 x 11 handwritten formula
sheet (both sides)
The Magnetic Effects of Currents
Make electric circuit:
What is the effect on the compass needle?
What if we switch polar
Series resistance, REQ =R1 + R2+ R3+ RN
Coulombs Law
Electric field of
q
inside
Capacitance
U electric = qV, V =
0
surface
Kirchoff node rule: currents into/out of node
sum to zero
surface
r
E n A =
1
4
U electric
q
For a single charge
Energy stored