CHEM 121 Lecture Notes - Lecture 13: Photon
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Lecture 13 - Wave-Particle Duality of Light, The photo electric
effect
Compton Scattering
• The collision between light and an electron
(Hyperphysics, R Nave)
• Electron and light are deflected at an angle
• Incoming light acts like a particle, collides with the electron and deflects in the process
• Although photon has no mass, this equation gives the photon energy as E=pc, the
particles obey the de Broglie relation,
• Important equation:
• p = momentum of photon
• c = speed of light
• h = Planck’s constant
• = wavelength
• = frequency
• This equation shows the energy of a photo is directly proportional to its frequency
Exercises:
1. Microwaves ovens are only allowed by law to operate at one frequency, 2450MHz
1. What is the wavelength of these microwaves in cm?
2. What is the energy of these microwave photo in Joules/moles
