NASSP Self-study Review 0f Electrodynamics. Created by Dr G B Tupper [email protected] The following is intended to provide a review of classical electrodynamics at the 2 nd and 3 rd year physics level, i.e. up to chapter 9 of Griffiths book, preparatory to Honours.
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The following is intended to provide a review of classical electrodynamics at the 2nd and 3rd year physics level, i.e. up to chapter 9 of Griffiths book, preparatory to Honours.
You will notice break points with questions. Try your best to answer them before proceeding on – it is an important part of the process!
Determine
constant
Transverse
Wavelength
Period
A monochromatic plane-polarized wave propagating in the z-direction has Cartesian components in phase:
.
In contrast, a circularly-polarized wave propagating in the z-direction has Cartesian components
i
Determine the corresponding magnetic field.
Determine the instantaneous energy-density and Poynting vector.
Polarization: dipole moment
per unit volume
Free charge density
Dielectric constant
Magnetization: magnetic moment per
unit volume
=0
Q.E.D.
Free current density
Conductivity
New
Index of refraction
Transverse
Phase
Attenuation!
Frequency dependant: dispersion
Good insulator
Good conductor
Note: at very high frequencies conductivity is frequency dependant
Good conductor
What one calls a “good conductor” or “good insulator” is actually frequency dependant; i.e. is
or ?
Find the value of for pure water and for copper metal. Where does it lie in the electromagnetic spectrum in each case?
For each determine the high-frequency skin depth.
For each determine the skin depth of infrared radiation ( ).
In the case of copper, what is the phase velocity of infrared radiation?
In the case of copper, what is the ratio for infrared radiation?
…dynamically
Damping (radiation)
“Restoring force”
Driving force
Natural frequency
Number of atoms/molecules per unit volume
Absorption coefficient
Ignore paramagnetism/diamagnetism
Frequency dependent: dispersion
Anomalous dispersion
Electron mass
No restoring force!
Electron number density
Drude model
Purely imaginary!!
Dispersion relation
Plasma frequency
F&F 2013 L46