Every point on an advancing wave front provides a new point of source for the wave
Predicts reflection, refraction und diffraction
Maxwell’s equations
All related equations and observations to electricity and magnetism into 4 little equations
The electromagnetic spectrum
The product of wavelength and frequency is speed is the speed of the wave:
Photon
Relationship between frequency and photon energy Planck’s Assumption:
Photons have momentum but no mass
Momentum of photon
As wavelength increases of a photon, frequency decreases and energy decreases.
As wavelength decreases of a photon, frequency increases and energy increases.
Photoelectric effect Shining light on a metal causes electrons to be emitted
Below some frequency, no photons are emitted regardless of intensity of light.
As frequency of the light increases, the kinetic energy of the emitted electrons increase.
As the intensity of the light increases under a certain frequency, the number of the electrons ( current I) increases.
Photon energy is quantized.
Some energy is needed to liberate an electron form a material. This amount of energy is called the Work Function Φ.
Wave-like nature of electrons
De Broglie: electrons (matter in general) displays wave-like behavior.
Double slit experiment: http://www.youtube.com/watch?v=FeCV27-mk0I
Photons behave like waves, proven by the double slit experiment.
Wavelength of an electron
Momentum of an electron
Emission spectra
High voltage is applied in a gas introduced vacuumed tube with metal electrodes.
Once a current is flowing the gas atoms get excited and this results in light mission.
When light is emitted, its due to the electrons going for an excited state to a non-excited state. The amount of energy released in this light is:
Rydberg Formula