Quantum Phenomena

Quantum Phenomena

1. The Photoelectric Effect

   • Work Function
     • MINIMUM AMOUNT OF ENERGY NEEDED TO REMOVE JUST ONE ELECTRON FROM THE METAL'S SURFACE
   • Threshold fequency
     • F0  planks constant multiplied by threshold frequency is the work function THE MINIMUM FREQUENCY WILL RELEASE A PHOTOELECTRON
     • h x threshold frequency= work function
   • Photoelectric equation
   • We can give a metal a negative charge on an electroscope and the gold foil rises- if we shine UV light at the metal electrons are released from the surface and it discharges so the gold foil can relax
   • einstein concluded...
     • light is made of particles called photons
     • an electon receives all the energy from one photon
     • the energy of a photon depends on it's frequency

2. Collisions of electrons with atoms

   • electron volts
   • ionisation and exitation
   • Fluorescent tubes

3. Energy levels and photon emission

   • Using line spectra
     • evidence of transition between discrete energy levels in atoms
   • hf=eone-etwo
   • states
     • Ground State
       • ELECTRONS IN AN ATOM ARE AT THE LOWEST POSSIBLE ENERGY LEVELS
     • Exited
       • ELECTRONS GAINED ENERGY- PROMOTED TO HIGHER ENERGY LEVELS
     • Ionised
       • ELECTRON GAINED ENOUGH ENERGY TO LEAVE THE ATOM

4. Wave-Particle Duality

   • electron diffraction suggests the wave nature of particles
     • INTERFERRENCE ALSO SHOWS THAT EM SPECTRA ACT LIKE WAVES
   • photoelectric effect suggests the particle nature of em waves
   • de Broglie wavelength equation
   • EK= 1/2 X MX V^2
   • ELECTRONS ARE ALSO shown as particles by electrolysis

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