how is light formed?

Answer 1

Planck's radiation law: http://en.wikipedia.org/wiki/Planck%27s_law basically implies that any object warmer than absolute zero emits radiation, and so objects that are extremely warm will emit visible light.

From quantum mechanical arguments related to planck's Law, all light is generated as a consequence of electron energy transitions, i.e., when an electron drops in energy level within the atom, a photon is emitted. If the energy change is sufficiently large, the photon's wavelength is in the visible band.

The corollary is the any electron transition, particularly those that are generated by chemical or electrical processes will also result in photon emission and light.

Answer 2

Well, actually, "light" is an act of creation. The reason this is stated is that everything runs downward from this value. It is the basis of entropy, or why our universe is "falling apart". Light energy (electromagnetic) appears to be formed of a particular form of energy called "Plank's Constant". It is a very small energy value that is also coupled with the value of "c". In the physics trilogy, E = mc2, m = E/c2, and c2 = E/m we note in the last equation how a gravitational field is formed. It is an energy value arising from a mass to energy ratio. This form of energy being released appears to be that of "h" - Plank's Constant. At http://timebones.blogspot.com and http://360.yahoo.com/noddarc there is a short writing entitled "The problem and Repair of Relativity" that may be of interest.

Answer 3

Accelerated electric charges (usually electrons) will emit light (electromagnetic radiation).
This was predicted by Maxwell and demonstrated by Hertz.