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Transcript of 1 | Teacher‘s Lab at CERN Teacher‘s Laboratory. 2 | Teacher‘s Lab at CERN Teacher‘s...
2 | Teacher‘s Lab at CERN
Teacher‘s Laboratory at CERN
• 5 classroom experiments– Cathode ray tube– Fine beam tube– Electron diffraction tube– Photoelectric effect– Electron spin resonance
• Video conference equipment
• Green wall
3 | Teacher‘s Lab at CERN
Cathode ray tube
• Study cathode rays• Deflection by electrical and (or) magnetic field• Cathode ray tube = electron accelerator• Example for oscilloscope and (no flat-screen) TV
5 | Teacher‘s Lab at CERN
Fine beam tube / Thomson-experiment
• Study Cathode rays.• Study Lorentz force.• Study of the deflection of electrons in a magnetic field into
a circular orbit.• Determination of the specific charge of the electron.
6 | Teacher‘s Lab at CERN
Fine beam tube / Thomson-experiment
Electron gun
Anode
Magnetic field (dipole)
7 | Teacher‘s Lab at CERN
Electron diffraction tube
• Determine the interplanar spacing of graphite using de Broglie relation and Bragg’s reflection
• Related topics and concepts:– Wave-particle duality (X-ray vs. electron)– Bragg’s reflection– Study small structure (inaccessible to optical)
8 | Teacher‘s Lab at CERN
Electron diffraction tube
UA
CathodeControl grid
Anode
Flourescent screen
Graphite foil
9 | Teacher‘s Lab at CERN
Photoelectric effect
• Verify the photoelectric effect.• Calculate Planck’s constant h• Show that the kinetic energy of the electrons is
independent of the intensity of the light.
10 | Teacher‘s Lab at CERN
Photoelectric effect
Cathode Circular Anode
V
High pressure Mercury lamb
Interference filters
12 | Teacher‘s Lab at CERN
Electron spin resonance
• Model of electron spin resonance demonstrating the interaction between the magnetic moment of the electron spin with a superimposed direct or alternating magnetic field
• Related topics and concepts:– Larmor precession– Revise resonance, gyroscope (not main focus)
• Caveat– No classical equivalent to spin concept!– This is just to help student form some mental model