Chapter 03 Experimental Basis for Quantum Theory General Bibliography 1) Various wikipedia, as...
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Transcript of Chapter 03 Experimental Basis for Quantum Theory General Bibliography 1) Various wikipedia, as...
Chapter 03Experimental Basis for
Quantum Theory
General Bibliography1) Various wikipedia, as specified
2) Thornton-Rex, Modern Physics for Scientists & Eng, as indicated
Version 110920, 110921
Outline
• 3.1 X-rays and Electrons• 3.2 Electron Charge• 3.3 Line Spectra• 3.4 Quantization• 3.5 Blackbody Radiation• 3.6 Photoelectric Effect• 3.7 X-Ray Production• 3.8 Compton Effect• 3.9 Pair Production & Annihilation
3.1 X-rays and Electrons
Geissler tubes~1857
http://physics.kenyon.edu/EarlyApparatus/Static_Electricity/Geissler_Tubes/Geissler_Tubes.html
http://www.oneillselectronicmuseum.com/page9.html
http://www.beer-neon-signs.com/category/neon-business-signs
3.1 X-rays and Electrons
Crookes Tubes~1869
http://www.magnet.fsu.edu/education/tutorials/museum/crookes_tube.html
Cathode rays (now called electrons)
Discovered cathode rays could be shifted by a magnet
X-rays and Electrons
Hand mit Ringen (Hand with Rings): print of Wilhelm Röntgen's first "medical" X-ray, of his wife's hand, taken on 22 December 1895 and presented to Ludwig Zehnder of the Physik Institut, University of Freiburg, on 1 January 1896[17][18]
X-rays and Electrons
1896 plaque published in "Nouvelle Iconographie de Salpetriere", a medical journal. In the left a hand deformity, in the right same hand seen using radiography. The authors designated the technique as Röntgen photography.
X-rays and ElectronsJJ Thomson
http://www.scifun.ed.ac.uk/pages/pp4ss/pp4ss-eoverm.html
http://ixnovi.people.wm.edu/Onebeautifulexperiment2008/emexperimentbywilliamsendor3.html
Charge of the Electron
3.3 Line Spectra
Pink Floyd: Dark Side of the Moon
http://intro.chem.okstate.edu/1314f00/Lecture/Chapter7/Lec11300.html
http://nothingnerdy.wikispaces.com/DIFFRACTION+GRATING
http://www.chem1.com/acad/webtext/atoms/atpt-3.html
nmk
k
456.364
2
2
k = 3,4,5,6
2
1
4
1
56.364
41
k
22
111
knRH
nmk
k
456.364
2
2
RH = 1.097e+7 m
3.3 Line Spectra
Lym
an n
=1
Balm
er n
=2
Pasc
hen
n=3
Bra
cket
t n=4
Pfund
n=5
100
nm
1000
nm
1000
0 nm
vis
3.5 Blackbody Radiation
http://www.mytightride.com/fof1fefl.html
3.5 Blackbody Radiation
http://phet.colorado.edu/sims/blackbody-spectrum/blackbody-spectrum_en.html
http://www.freefoto.com/preview/11-12-52/Electric-Light-Bulb
http://en.wikibooks.org/wiki/Wikijunior:How_Things_Work/Light_Bulb
3.5 Blackbody RadiationWein’s Law
Stefan-Boltzmann Law
428106705.5
Km
Watts
= 1 for perfect blackbody
T
Kmimum
3
max
10898.2
4TIntensityTotal
3.5 Blackbody Radiation
4
2
kTc
Intensity
IRUV
3.5 Blackbody Radiation
1
12/5
2
kThce
hc
Max Planck assumed some sort of oscillators filled the cavity AND energy difference between standing wave modes = h f
Planck’s Radiation Law
h = 6.626e-34 Js
3.6 Photoelectric Effect
Heinrich Hertz
http://en.wikipedia.org/wiki/Heinrich_Hertz
Verified Maxwell equations prediction of electromagnetic waves
http://en.wikipedia.org/wiki/Induction_coil
~1887
3.6 Photoelectric Effect
Photoelectric Effect Investigations~1900
1. Higher intensity light did not change the point at which current started to flow. (i.e. energy of the electrons)1’. More total incident energy did not increase the energy of individual electrons.
2. Different colors of light changed the starting point for current flow.
3.6 Photoelectric Effect
hfeVoWork function
Energy of an individual photon
Implications: 1. EM waves have fixed energies (EM field is quantized) 2. Electrons are bound in a material by an amount determined by the composition
typically a few Volts at most
3.7 X-Ray Production(Bremsstralung + Characteristic X-Rays)
Roentgen
min max Energy
characteristic lines
hc
E
cf
hfE
photon
photon
At fixed HV 35kV
3.7 X-Ray Production(Bremsstralung + Characteristic X-Rays)
Roentgen
3.7 X-Ray Production(Bremsstralung + Characteristic X-Rays)
http://en.wikipedia.org/wiki/Cathode_ray_tube
Do TV Sets Give Off X-Rays?
X-rays may be produced when electrons, accelerated by high voltage, strike an obstacle while traveling in a vacuum, as in a TV containing a cathode ray tube (CRT). Since many of the components in television sets operate at thousands of volts, there is the potential for x-ray generation. These components may produce x-rays capable of escaping from the television receiver or CRT. This unintentional emission of x-radiation can pose a potential hazard and must be controlled.
http://www.fda.gov/Radiation-EmittingProducts/ResourcesforYouRadiationEmittingProducts/ucm252764.htm
http://www.orau.org/ptp/collection/xraytubescoolidge/xraytubescoolidge.htm
http://www.tradevv.com/chinasuppliers/eiffelgu_p_23e13/china-Portable-X-ray-flaw-detector-ceramic-tube.html
http://www.aerospacendt.com/Radiography.htm
Computed tomography (CT) scanning, also called computerized axial tomography (CAT) scanning, is a medical imaging procedure that uses x-rays to show cross-sectional images of the body.A CT imaging system produces cross-sectional images or "slices" of areas of the body, like the slices in a loaf of bread. These cross-sectional images are used for a variety of diagnostic and therapeutic purposes.
How a CT system works:
http://www.fda.gov/Radiation-EmittingProducts/RadiationEmittingProductsandProcedures/MedicalImaging/MedicalX-Rays/ucm115317.htm
http://www.strokecenter.org/patients/diagnosis/ct.htm
http://www.strokecenter.org/patients/diagnosis/ct.htmhttp://medicaltools.onsugar.com/Ct-Scan-Abdomen-Cancer-15819123
http://info.shields.com/bid/43193/MRI-Images-torn-ACL-and-normal-ACL
Fluoroscopy is an imaging technique commonly used by physicians to obtain real-time moving images of the internal structures of a patient through the use of a fluoroscope. In its simplest form, a fluoroscope consists of an X-ray source and fluorescent screen between which a patient is placed. However, modern fluoroscopes couple the screen to an X-ray image intensifier and CCD video camera allowing the images to be recorded and played on a monitor.
http://en.wikipedia.org/wiki/Fluoroscopy
3.8 Compton EffectThomson Scattering
In classical description, scattering occurs via dipole and scattered photon of same frequency (wavelength)
3.8 Compton Scattering
cos1' mc
h
h/mc =2.2426e-12 m
3.9 Pair Production & Positron Annihilation
MeVcmhfifonly e 022.1)511.0(22 2
Pair Production
3.9 Pair Production & Positron Annihilation
Positron Annihilation
Photons come out back-to-back
Photon energies are 0.511 MeV each
Positron emission tomography (PET) is a nuclear medicine imaging technique that produces a three-dimensional image or picture of functional processes in the body. The system detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide (tracer), which is introduced into the body on a biologically active molecule. Three-dimensional images of tracer concentration within the body are then constructed by computer analysis.
http://en.wikipedia.org/wiki/PET_scanner
If the biologically active molecule chosen for PET is FDG, an analogue of glucose, the concentrations of tracer imaged then give tissue metabolic activity, in terms of regional glucose uptake.
http://archives.drugabuse.gov/newsroom/03/NR9-08.html
Summary of Chapter 03Strange things not known from classical physics
• New things– Cathode rays electrons– X-rays
• Line spectra– Gaseous discharges show lines rather than continous spectrum
• Blackbody radiation– Rayleigh-Jeans classical formula clearly incorrect at explaining
spectrum– Planck: oscillators with fixed energies
• Compton scattering– Scattered photons have different wavelength in contast to
classical description• Pair production & Positron annihilation
– Waves change into particles and vice versa