What is the difference between a laser and a light bulb?

A laser produces coherent light, meaning the light waves are in phase and travel in a single direction, resulting in a narrow, focused beam. In contrast, a light bulb emits incoherent light, with waves that are out of phase and spread out in multiple directions, creating a broader, less focused illumination. Additionally, lasers typically operate at a specific wavelength, while light bulbs emit a wide spectrum of wavelengths. This difference in light production leads to distinct applications, with lasers commonly used in precision tasks and light bulbs used for general lighting.