So if you turn a flash light on the light that comes out does it have to accelerate up to the speed of light or is it istantly at the speed of light when you turn the flashlight on? thnk
Light photons are generated when energized electron orbiting atoms (or molecules) de-energize and return to rest orbits. The photon leaves the atom at the speed of light (no acceleration) with a wavelength that is characteristic of the excess energy given up by the electron (and therefore characteristic of the particular element).
Light's always at the speed of light. Of course, it isn't necessarily at the speed of light in a vacuum.
Light does not accelerate; it is always travelling at 3 x 10^8 m/s (In a vacuum that is). It travels slower through air, but always at the same speed.
Light always travels at the speed of light (not just physically, but by definition also! This means if light slowed down, our definition for the length of 1 meter and 1 second would also change, in such a way that there would actually be no difference! Im referring to the speed of light in a vacuum here, not its speed through any medium) Think of light as huge numbers of tiny particles (photons). When the filament in the globe gets hot enough to produce light, the atoms in it will randomly emmit a photon, but the photon always travels at the speed of light, as long as it exists. When you have huge numbers of atoms all randomly emitting photons at random moments, it starts to look like a continuous stream of photons. Each individual photon however always travels at the speed of light (this speed actually varies depending on the medium, like glass, air water etc.)
