Final answer:
A plane mirror reflects light to form a virtual image that is laterally inverted and at the same distance behind the mirror as the object is in front of it. Plane mirrors do not focus laser beams or have functions directly related to laser cavities or industry applications.
Step-by-step explanation:
The function of a plane mirror is to reflect light in such a way that an image is formed. The image created by a plane mirror is referred to as a virtual image because it cannot be projected onto a screen; it appears behind the mirror at the same distance that the object appears in front of it. The orientation of the image is the same as the object, but it is laterally inverted.
Plane mirrors do not focus light into a small spot, allow laser beams out of resonator cavities, close off resonator cavities, or angle laser beams towards workpieces. These functions are associated with other types of mirrors or optical components in laser systems.
In general, lasers have a wide range of applications including measuring distances, cutting materials in industrial processes, producing holograms, and medical procedures such as destroying cancer cells. Their precise directionality and intense, narrow beam make them ideally suited for these tasks.