Download The Compton Effect, or Compton scattering – conclusive evidence

The Compton Effect, or Compton scattering – conclusive evidence for the particle nature of light
Arthur H. Compton won the 1927 Nobel Prize for Physics for his confirmation of the photon particle
nature of light in his discovery that X-rays scattered by carbon target atoms had a longer wavelength
than the original x-ray photons. The scattered x-rays had lost energy.
Where did the extra energy go? The energy lost by the x-ray photons, as evidenced by the photons’
increased wavelength, increases the kinetic energy of the scattered electrons. Sound like billiards? It
should! The collision is inelastic – kinetic energy is not conserved, although total energy is (see p.483 of
Pearson). As in all phenomena, momentum is conserved.
Because of Einstein’s work which showed that mass and energy are continuous, or equivalent, which
produced the equation, 𝐸 = 𝑚𝑐 2 , Compton was able to show that a photon actually had momentum,
where
𝑝=
ℎ
𝜆
The impulse of photons in the Compton effect gives great evidence that light travels in the form of
photon particles. The laws of conservation of momentum and of energy apply.
Investigate the Compton effect using
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Apply
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http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/comptint.html
https://www.youtube.com/watch?v=Y_F7acYIxhw
https://www.youtube.com/watch?v=lti6hxNkgT4
And Billy, you’ll like https://www.youtube.com/watch?v=0sdX1_msmAU
light-as-particle ideas,
Compton’s momentum equation,
the nature of inelastic collisions,
and the laws of conservation of vector
momentum and of scalar energy
to describe and explain the Compton effect.
The photoelectric effect and the Compton effect are the major
evidence pieces for the particle nature of light.
 PE effect problems - p.718#1,2; p.719#1,2; p.720#1,4-6
 C effect problems - p.723 #1-3; p.724#1; p.725 #1-4,6,7