1905 - Einstein
The emission of electrons from a surface (usually metallic) upon exposure to, and absorption of, electromagnetic radiation.
The photoelectric effect was explained mathematically by Einstein who extended the work on QUANTA as developed by Planck.
1909 - Robert Millikan
This experiment determined the magnitude of the electronic charge, and that it was QUANTISED.
This value is approximately
Note: An electron volt (eV) is the amount of energy it takes to accelerate one electron through a potential of one volt. Thus, 1eV
Prince Louis de Broglie - 1932
De Broglie discovered that all particles with momentum have an associated wavelength.
What is the wavelength of a human being, assuming he/she weighs 70 kg, and is running at 25 m/s?
1898 - Thomson
1913 - Rutherford/Bohr
Atomic Line Spectra
Lyman: n>1 (ultraviolet)
Balmer: n>2 (visible)
Paschen: n>3 (infrared)
Brackett: n>4 (infrared)
Pfund: n>5 (infrared)
Energy and frequency:
The photoelectric effect:
De Broglie wavelength:
Equations of interest (non-examinable!)
Anyone who has not been shocked by quantum physics has not understood it.
The word 'quantum' refers to this peculiar aspect of nature that goes against common sense.
Very interesting theory - it makes no sense at all!