Transcript Welcome to Electricity & Magenetism

PYSICS 30471
Electricity & Magnetism
Tuesday and Thursday 12:30-1:45
At DeBartolo, Room 119
By Prof. S. Frauendorf
125 NSH 1-3875 [email protected]
Office hours: Tuesday and Thursday 10:30-11:30
Homework:
Every week, due on Tuesdays by 16:00.
Will be provided as MS doc file in the 30471 course space.
Late homework policy: Turned in
within the week of the deadline:
75%
within the following week:
50%
later:
0%
Graded HW back after 2 weeks.
Grade
Midterm Exam
Final Exam
Homework
30%
40%
30%
Grades available on WebCT
Teaching assistant: Sun Jie(Jason) , room 120 tel.:1-4743
[email protected]
Style
Combination of
Powerpoint slides
containing the most important results
available in the course space phys30471.01
I:\coursefa.06\phys\phys30471.01
and handwritten notes
derivations, explanations, …
Syllabus
Text: Introduction to Electrodynamics,
David J. Griffiths, (3rd ed. 1999 ), Chapters 1-7
1.
2.
3.
4.
5.
6.
7.
Vector Analysis
Electrostatics
Special Techniques
Electric Fields in Matter
Magnetostatics
Magnetic Fields in Matter
Electrodynamics
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What is electrodynamics,
and how does it fit into the
general scheme of physics?
Natural phenomena are governed by the electromagnetic interaction.
It governs our man-made world as well.
It keeps the molecules together.
Even where you do not expect it, the electromagnetic interaction is at work
Mechanics tells us the reaction
of a body to a force.
Forces are given.
Electromagnetism is the theory
two types of forces:
Electric force
Magnetic force
Classical Mechanics
Newton
small
Quantum Mechanics
Bohr, Heisenberg,
Schrödinger, …
fast
Special Relativity
Einstein
Quantum Field Theory
Dirac, Pauli, Feynman,
Schwinger, ….
Electric Charge (q, Q)
1. Charge exists as +q and –q. At the same point: +q-q=0
2. Charge is conserved (locally).
3. Charge is quantized. +q =n (+e), -q = m (-e), m, n, integer
electron: –e, positron: +e, proton: +e, C-nucleus: 6(+e)
Charge conservation in the micro world:
p + e -> n (electron capture)
Macro world: q ~1023e
Quantization is unimportant. Imagine charge as some kind of jelly.
The Field Formulation
E
q
q
F
q
Light wave
v=c
Four kinds of forces - interactions
1.
2.
3.
4.
Strong
Electromagnetic
Weak
Gravitational
Keeps nuclei and nucleons together.
Most common phenomena.
β-decay n->p+e+ν
Keeps the Universe together.
Unification
electric + magnetic
electromagnetic
electromagnetic + optic
electrodynamic
electrodynamic + weak
electroweak
In Quantum Field theory the
difference between particles
and forces becomes rather
diffuse.
Two types of quantum particles:
Fermions and Bosons.
SI-Units
Systeme Internationale
Mechanics
length: meter (m)
mass: kilogram (kg)
time: second (s)
force: newton ( N  kgm s 2 )
work: joule (J = N m)
Power: watt (W = J/s)
Electromagnetism
current: ampere (A)
charge: coulomb (C = As)
voltage: volt (V )
work: (W s = V A s)
power: watt (W = V A)
The equations of EM contain
 0  8.859  10
12
As
Vs
1
, 0  4  107

,
2
Vm
Am  0c
Nm2
9 Vm
 9  10

9

10
40
C2
As
1
9