Thursday, August 11, 2011

What is quantum theory?

Quantum mechanics is also known as quantum physics or quantum theory. It is a branch of physics that studies about dual nature of matter and energy - particle and wave nature. The first concrete explanation for the phenomenon of the black body radiation was given by Max Plank in 1900.
Quantum theory gives explanation for the nature of matter. And also it explains how matter behaves on various atomic or even subatomic levels. Quantum mechanics is closely related to quantum theory, of which it is a branch of. This theory states that matter is made of individual and quantifiable units. This theory was formulated by German physicist Max Planck. He first submitted his theory to German Physical Society.

Radiant energy is propogated in small packets and these packets are called quantum. When solids are heated, they emit radiation over a wide range of wavelengths. For example, when an iron rod is heated in the furnace, it first turns to dull red and then progressively becomes more and more red as the temperature rises. As this is heated further, the radiation emitted becomes white and then becomes blue as the temperature becomes very high. In terms of frequency, it means that the radiation emitted goes from a lower frequency to a higher frequency as the temperature increases. The red colour lies in the lower frequency region while blue colour belongs to the higher frequency region of the electromagnetic spectrum. The ideal body, which emits and absorbs all frequencies , is called a black body radiation. The exact frequency distribution of the emitted radiation from a black body depends only on its temperature. At a given temperature, intensity of radiation emitted increases with decrease of wavelength, reaches a maximum value at a given wavelength and then starts decreasing with further decrease of wavelength.