Waves and Particles Nuclear Physics

Waves and Particles Wave Particle Duality Black Body Radiation The Photo-electric Effect The Compton Effect De Broglie Wavelength Heisenberg Uncertainty Principle

Wave - Particle Duality Waves exhibit particle-like characteristics Particles exhibit wave-like characteristics Young’s Double-Slit Experiment using a stream of electrons showed a similar deflection pattern to light wave

Blackbody Radiation All bodies radiate electromagnetic waves. Blackbodies are objects that absorb all electromagnetic waves that fall on them. Materials that are good absorbers are good emitters. Materials that are good reflectors (like polished silver) are poor emitters. Max Planck stated that objects emit energy at integer multiples of the frequency of the wave emitted.

Planck’s Equation E = n h f Where E is energy, n = 0,1,2,3,…, f is the frequency of the wave and h is Plank’s Constant, Planck’s Constant(h) = 6.6260688 X 10-34 Js These energy packets have a value = hf

Planck’s equation verifies Einstein’s earlier claim that light consists of energy packets He received the Nobel Prize in 1918 for his work on Quantum Theory.

The Photoelctric Effect Photons hit metal surface with sufficient frequency Energy from photons creates a current Photo cells are commonly used in various detection systems (garage doors, alarm systems, etc.)

The Compton Effect Aurthur Compton Decrease in energy (increasing wavelength l) when photons interact with matter. Compton used x-rays and gamma rays to prove Einsteins Photoelectric Effect/Photon theories. Inverse Compton Effect occurs when photons gain energy from their interaction with matter.

Compton Effect Mathematical Explanation: h f = h f´ + KE Arthur Compton Nobel Prize 1927 Mathematical Explanation: h f = h f´ + KE Energy of incident energy of Kinetic Energy gained Photon scattered photon by scattered electron.

DeBroglie and the Wave Nature of Matter Using the wave-particle duality work done by Einstein and Planck, De Broglie stated that ALL objects that move have a wavelength similar to a wave associated with them.

The De Broglie Wavelength De Broglie stated that the wavelength of any particle or object is inversely proportion to its momentum (p). l = h / p Where l = wavelength h = Planck’s Constant p = Momentum (m v)

De Broglie Wavelength Verified experimentally by several physicists in the U.S. and in Europe The De Broglie Wavelength is only observable for very small masses (protons, neutrons, electrons, etc) Because the l for larger masses would be very small, diffraction and interference cannot be observed. (See example 5 in book)

The Heisenberg Uncertainty Principle Werner Karl Heisenberg Nobel Prize 1932 Limits the accuracy with which momentum and position of a particle can be described simultaneously These limits are imposed by nature and cannot or of the quality of the equipment used) Heisenberg’s Principle describes uncertainty between position and momentum as well as energy and time.

The Heisenberg Uncertainty Principle Momentum and Position (Dpy)(Dy) ≥ __h__ 4 π Where Dy = uncertainty in the particle’s y direction Dpy = uncertainty in the vertical component of the particle’s momentum. h = Planck’s Constant

The Heisenberg Uncertainty Principle Energy and Time Momentum and Position: (DE)(Dt) ≥ __h__ 4 π Where DE = uncertainty in the particle’s energy when in a certain state. Dt = Time interval that the particle is in that state h = Planck’s Constant

Congratulations!! If you understood all of this I am impressed because…. This is tougher than Rocket Science!!!