Quantum Phenomena

Quantum Phenomena

1. The photoelectric effect

   • the production of electrons or other free carriers when light is shone onto a material.
     • light has to be of a high enough frequency
       • Free electrons absorb energy from light
       • If the electrons absorb enough energy, the bonds holding it to the metal will break and the electron will be released
   • electrons emitted= photoelectrons
   • Kmax = E − ϕ
     • where E=hf
     • Kmax = hf − ϕ
       • where f= the threshold frequency
         • threshold frequency= the minimum frequency of incident light which can cause photo electric emission
       • work function= the minimum quantity of energy that is required to remove an electron from a metal
     • Kmax = h(ƒ − ƒ0)

2. Wave Particle Duality

   • It expresses the inability of the classical concepts "particle" or "wave"
   • Particle
     • Photoelectric Effect
   • Wave
     • Double Slit Experiment

3. Energy Levels

   • Excitation
     • the process in which an electron adopts a higher energy state when energy is supplied.
     • hf = E1 - E2
     • very shortly after becoming excited they drop back to the lower energy state
       • that means that they have to lose some energy and to do this they give out a packet of energy - a photon. The size of the photon equals the difference between the energy levels the particle has moved from
   • Ionisation
     • Represented on a energy level diagram as the highest level
       • when the electron has enough energy to leave the atom
     • Both occur when 2 electrons collide

4. De Broglie Wavelength

   • λ = h/mv
   • The de Broglie equation is an equation used to describe the wave properties of matter, specifically, the wave nature of the electron

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