Download - Quantum and Waves
Quantum and Waves:
University of Oxford
Next peergrade assignment 5 due Monday, February 3!Respond to your question on waves in an everyday context
4 different types of waves:
1. Electromagnetic and light (oscillating electric and magnetic fields)2. Mechanical (vibration of atoms, molecules, solids, spins, charges,…)3. Quantum (any particle)4. Gravitational waves
What is Quantum Physics?
1. Particle-wave duality (wave is particle, particle is wave)2. Non-locality (1 particle can be in two places at the same time) 3. Entanglement (spooky action at a distance)4. Statistics (spin)5. Fock space (almost infinite dimensions)
What is Quantum Physics?
1. Particle-wave duality (wave is particle, particle is wave)
Is electromagnetic radiation composed of particles?A. Yes
B. No
Radioactivity experiment
Radioactivity:
beta decay
The so-called weak force drives the radioactive transition:neutron (n) -> electron (β-)+proton (p) +neutrino (ν)This transforms cesium into barium. But the barium created is in a very high energy state so it quickly releases its energy by emitting a electromagnetic wave/particle (ϒ). This ϒparticle is what is measured with the Geiger counter.
ϒ
(source: Phys 339 lab notes)
Can you get gold from mercury by radioactivity?A. Yes
B. No
C. I hope so
Radioactive mercury will transform into gold!
Srce: Joao Pedro Araujo
Radioactivity:
beta decay
weak force: n -> electron + proton + neutrino + electromagnetic wave/particle
Perfect random process: Commercial random number generator base on radioactivity
www.imagesco.com/kits/random-number-generator.html
by Rob AtkinsonBathys Hawaii
Caesium atomic clock
U.S. Naval Observatory
(source: Phys 339 lab notes)
Geiger counter:
High energy electromagnetic radiation (ϒ-rays) behave like individual particles!
What about visible light?
Sun radiation:http://qdl.scs-inc.us/2ndParty/Pages/10522.html
Wave is particle
http://www.physast.uga.edu/~rls/1010/ch5/ovhd.html
Color
Temperature [K]
Hot bodies emit radiation
1.You press in the trigger to put the detector into "reference" mode.
2.An internal heat source, whose temperature is known, fires out infrared
radiation.
3.A mirror picks up the infrared.
4.A detector picks up the reflected infrared from the mirror.
5.A microchip notes the reading of the internal reference source.
6.Now you release the trigger to put it in operating mode.
7.The mirror swings back to face the front of the detector.
8.The hot sample you're interested in gives off its own pattern of infrared
radiation.
9.The infrared fires in through the front and bounces off the mirror into the
detector.
10.The chip compares the infrared wavelengths from the reference source
and the sample and figures out the sample's temperature.
Infrared thermometers are based on the principle of black body radiation: