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Atomic and Nuclear Physics

Quantum Theory

Max Planck was attempting to derive mathematical equations to describe the spectrum of the radiation given out by a hot body.

He found that his equations could not be made to agree with experimental data as long as he considered electro-magnetic radiation to be continuous.

He made the following suggestions

i) that electro-magnetic radiation is quantised (radiated in "packets" of energy called quanta or photons)
ii) that the amount of energy carried by each quantum is directly proportional to the frequency of the radiation.

The energy possessed by a quantum is given by

E = hf

or, in terms of wavelength

where h is now called Planck’s constant.

From these simple sounding statements developed what has been described as "the most successful scientific theory of all time": quantum mechanics.

 

© David Hoult 2008