Final answer:
Coherent light is characterized by light waves that have the same frequency and are in phase, maintaining a constant phase relationship and the same direction of polarization.
Step-by-step explanation:
A coherent light wave pattern is characterized by light waves that have the same frequency, amplitude and are in phase. These waves maintain a constant phase relationship with each other over time. Coherent light enables the formation of interference patterns, where constructive and destructive interferences can cause bright and dark fringes, respectively. Such coherence is critical in applications like lasers and holography. In contrast, an incoherent light wave pattern consists of light waves with different frequencies and phases, resulting in no fixed phase relationship, typical of light from conventional sources like a light bulb.
Electromagnetic waves, including light waves, possess an electric field (E) and a magnetic field (B) that oscillate perpendicular to the direction of propagation. Coherent light waves have the same direction of polarization, which is parallel to the electric field (E). Additionally, for coherent waves to be useful in various technological applications, it is not only important that they are in phase but also that they have a consistent direction.