Which of the following best describes the light emitted by a laser?

The light emitted by a laser is best described as coherent and monochromatic. Coherent light means that the light waves emitted by the laser are in phase with each other, which results in a well-defined direction and allows for minimal spreading of the beam over distance. Monochromatic refers to the light being of a single wavelength or color, which is characteristic of lasers, as they produce light at very narrow frequency ranges compared to other light sources.

This unique property of being coherent and monochromatic makes laser light highly useful in various applications, such as telecommunications, medical procedures, and optical devices, where precise control over light is essential. The combination of these characteristics allows lasers to produce highly focused beams, contributing to their effectiveness in cutting, scanning, and various forms of data transmission.

Other options present characteristics that do not accurately represent laser light. For example, incoherent and broad-spectrum light is typical of traditional light sources like incandescent bulbs and fluorescent lights, while options mentioning variability with input power or even distribution do not capture the fundamental and defining attributes of laser light.