Lots of different sources produce light ... Light can also be produced by stars, fires, light bulbs, torches, street lights, glowsticks, candles, lasers and even blue light from smartphones.

A light source created by a light emitting diode ... halogen and CFL fluorescent bulbs. LEDs draw considerably less power and are up to 80% more efficient, and they can last from 10 to 20 years.

You might have learned in school that Thomas Edison invented the light bulb, but the truth is much stranger (public domain) It has been known for a long time that passing a current through a wire ...