What is a laser and how does it differ from other light sources?
A laser emits Coherent light. this is a form of light, the constituent wave trains of which are emitted by a single source and move in unison. The LASER is the main source of such light.The output from a laser can be collimated into a tight beam which is very intense and highly controllable. In ordinary thermal light sources various portions of the heated filament emit light in random small bursts that lack the synchronization needed for coherent light. The light is out of phase with itself and has a great deal of scatter A laser is useful because it produces light that is not only of essentially a single frequency but also coherent, with the light waves all moving along together in unison. Light moves in the form of a wave, with crests and troughs. Like all other kinds of electromagnetic radiation, it can be characterized both by its frequency, or number of wave crests passing a given point per second, and by its wavelength, or distance between wave crests. Different wavelengths of li
