Sunday, November 23, 2008
What is the Quantum Theory of Radiation?
The advent of the twentieth century brought a lot of exciting discoveries in the world of Physics. The dawn of the breakthroughs was from the quantum theory of radiation by Max Planck in around 1900. A hot body radiates or absorbs energy in the form of packets called quanta; the radiation or absorption is not continuous but in discrete units. Each quantum carries an energy given by the product of a constant h ( the Planck's constant) and f (the frequency of the radiation). The value of h = 6.63x10^-34 J s. Albert Einstein in 1905 wrote a famous paper on the theory of photoelectric effect applying the quantum theory of radiation, which earned him the 1921 Nobel Prize in Physics. In fact, the Quantum theory of radiation is a kind of start of a new physics - Quantum Physics !