Plane mirrors are generally used to demonstrate the reflection of light in laboratories.

Explanation:
- Plane mirrors, also known as flat mirrors, have a flat reflective surface. They are made by coating a piece of glass with a thin layer of metal, such as aluminum or silver, on one side.
- When light rays strike the surface of a plane mirror, they undergo reflection. The incident rays of light bounce off the mirror's surface and form reflected rays. The angle of incidence is equal to the angle of reflection, and the reflected rays appear to come from behind the mirror.
- Plane mirrors produce virtual images, which means that the images formed by these mirrors cannot be projected onto a screen. The images appear to be located behind the mirror and are the same size as the objects being reflected.
- The use of plane mirrors in laboratories allows students to observe and study the properties of reflection. They can easily see how light rays reflect off the mirror's surface and understand the concept of angle of incidence equaling the angle of reflection.
- Plane mirrors are particularly useful for experiments involving the laws of reflection, such as the formation of multiple images or the measurement of angles. They are also commonly used in optical setups, such as periscopes or kaleidoscopes.
- Unlike convex mirrors, which have a curved reflective surface that causes light to diverge, and concave mirrors, which have a curved reflective surface that causes light to converge, plane mirrors provide a clear and undistorted reflection of objects.
- In addition to laboratory use, plane mirrors are also commonly found in daily life, such as in bathrooms, dressing rooms, and rearview mirrors of vehicles, where their reflective properties are utilized for practical purposes.

In conclusion, plane mirrors are the type of mirrors generally used to demonstrate the reflection of light in laboratories due to their flat reflective surface and ability to produce clear and undistorted reflections.