Like and unlike charges: similarities and differences.
Faraday ice pail experiment.
The coulomb
conductors and insulators
semiconductors
superconductors
electric force
Class 2
Forces in Nature
- strong
- electromagnetic
- weak
- gravitational
Newton’s Law of Universal Gravitation
How Newton knew the answer before he began (Halley anecdote and the falling apple).
The moon’s acceleration.
F = - {G m1 m2/r122}r12-hat
G = 6.67
x 10-11 N m2/kg2Are there “point” masses?
Why Newton invented calculus.
Class 3
Coulomb’s Law
“point” charges
F = {k q1 q2/r122} r12-hat
k = 9
x 109 N m2/C2Comparison of gravitational and electrical forces between particles.
The bullet model of forces.
The vector character of the inverse-square forces.
“weightlessness”
Class 4
Fields
influence felt all through space (permeating space)
vector character of the field
Example: tides
connection of charge to field
Electric field
test charge
E = {k q /r2} r-hat
Gravitational field
test mass
unit of electric, gravitational field
Lines of Force and Field
Faraday and “lines of force” and the field concept
Can field lines cross?
the electric dipole
Class 5
Calculating the field for distributions of charges and masses
What we need to do to go from “point” charges and masses to real charges and masses.
dE = {k dq /r2} r-hat
The key is in defining the infinitesimal charge or mass.
Class 6
Gauss’s Law
flux defined:
FErelevance of flux
The Gaussian surface--what it means
The easy way to calculate fields (assuming symmetry).
Examples of use of Gauss’s Law:
FE = 4p k qenclosedClass 7
Magnetism
the vector (“cross”) product
F = q v
x BClass 8
Lorentz Force
F = q {E + v
x B}The cyclotron and how it works.
Class 9
Gravitational and electrical potential energy
More on potential energy curves and allowed motions of particles.
Class 10
Potential
Still another way to calculate fields.
Batteries and EMF. What EMFs do.
Class 11
Capacitance
What does “ideal capacitor” mean?
Calculating capacitances for different physical situations. Why capacitance is geometrical in nature.
Class 12
Capacitors in series and parallel
Energy storage in capacitors.
Class 13
Batteries and Bulbs
What current is.
the mnemonic i = navy (actually i = nAve).
The independence of current density from geometry.
Working with batteries and bulbs to predict how bright/dim bulbs are from first principles (and experience).
Microscopic views of conduction and Ohm’s Law.
Why resistance is geometric; resistivity.
Class 14
Current and Resistance
Working with batteries and bulbs and resistance in more complex circuits.
Combining ohmic resistors in series and parallel.
Class 15
Power
Power in circuits.
Ohm’s Law revisited.
P = Vi, and why.
Class 16
complex circuits
Kirchhoff’s Rules (junction rule, potential rule)
Class 17
RC circuits
What happens in RC circuits--and why Kirchhoff’s rules help.
Knowing the answer before you begin to work the problem.
Class 18
Ampere’s Law I
Integral of B(dot)dl = 4
p k-prime ienclosed.The magnetic field around a current-carrying wire.
Forces between current-carrying wires.
Class 19
Ampere’s Law II
The law of Biot and Savart, the counterpoint to Coulomb’s Law and Newton’s Law of Universal Gravitation:
dB = {k-prime i dl
xr-hat /r2}Class 20
Faraday’s Law
Changing flux causes a current to flow.
Currents flow because of EMFs.
Changing fluxes cause EMFs: EMF proportional to d
FB/dt.Lenz’s Law: the current flows in such a way as to try to return the magnetic field to its prior value.
The change in the flux is such that the flux attempts to be returned to the previous value.
The full form of Faraday’s Law: EMF = -d
FB/dt.Class 21
Inductance
self inductance, L
mutual inductance, M
Why inductance is geometric in nature.
The connection of flux and inductance.
Combining inductances and Kirchhoff’s rules.
Class 22
Oscillations in circuits
SHM reprise
reactances and circuits
Class 23
Electromagnetic waves
transverse waves
wave speed: c = f
lHuyghens’s Principle
Are electric and magnetic fields really just shades of one another? (Another look at special relativity, and why Einstein was driven to it.)
Class 24
Wave and particle properties of EM
constructive and destructive interference
Young’s experiment.
Why we know light is a wave.
Diffraction formulas.
The principle of seeing by waves scattering and how it works: to see an object of size d, we must use a wavelength
l comparable to d; the de Broglie relation tells us about its momentum, and this energy.More on Einstein’s annus mirabilis, 1905
Why we know light is a particle.
Class 25
Compton effect; Uncertainty Principle
![[Heisenberg]](heisenberg.GIF)
The photoelectric effect: light behaves as a particle (originally called the light quantum).
The Compton effect: light behaves as a particle.
Are electrons waves or particles? The Davisson-Germer experiment.
Waves or particles?
Class 26
atoms and nuclei
I shoot an arrow in the air, it falls I know not where: determining the cross-section by firing particles at things: d
s/dW.Thomson and the plum pudding model of atoms (the first model).
Rutherford’s contribution to understanding atoms.
Scattering of alpha particles, the Geiger-Marsden experiment, and why Rutherford was surprised.
Class 27
Interaction of fields with matter
Looking at how close approaches of atoms and charged particles work.
The energy-loss formula: calculating -dE/dx.
Bethe’s result for scattering energy loss.
Class 28
Applied electromagnetism
linear accelerators
How energy of particles depends on speed.
Van De Graaff accelerators
phase stability--an important quality of accelerators
the cyclotron revisited
The difference between lab and CM frames
Class 29
More applied electromagnetism
Using interactions to detect particles and identify them.
The energy-loss formula: -dE/dx.
The tradeoff between having enough energy loss to detect something and not so much that it changes the path substantially and throws off the results.
Different kinds of detectors, and how they are used.
- Geiger-Müller counter
- cloud chamber
- nuclear emulsion
- photomultiplier
- scintillator
- sodium iodide crystal
- bubble chamber
- spark chamber
- drift chamber
- multiwire proportional chamber
- silicon drift detectors
- semiconductor diode detector
- calorimeter
Modern detector ideas--throw in everything but the kitchen sink.
4
p detectorstake me to the journal assignments
aubrecht@mps.ohio-state.edu [latest revision, 4 December 2000]