An object is placed between two parallel plane mirrors. The number of images formed is

four
one
two
infinite

The correct answer is (c).

When an object is placed between two parallel plane mirrors, an infinite number of images are formed. This is because each image acts as an object for the other mirror, and the process repeats indefinitely. The images are all the same size as the object, and they are located symmetrically between the mirrors.

The first image is formed directly behind the object, and the other images are formed at regular intervals between the first image and the mirrors. The distance between two successive images is equal to the distance between the mirrors.

The images are virtual, upright, and laterally inverted. This means that they appear to be behind the object, they are upright, and they are flipped left to right.

The number of images that can be seen depends on the angle between the object and the mirrors. If the object is placed perpendicular to the mirrors, then an infinite number of images will be formed. However, if the object is placed at an angle to the mirrors, then only a finite number of images will be visible.

The following diagram shows the formation of images when an object is placed between two parallel plane mirrors:

[Diagram of an object placed between two parallel plane mirrors, showing the formation of an infinite number of images]

The object is represented by the black dot. The first image is formed directly behind the object, and the other images are formed at regular intervals between the first image and the mirrors. The distance between two successive images is equal to the distance between the mirrors.

The images are virtual, upright, and laterally inverted. This means that they appear to be behind the object, they are upright, and they are flipped left to right.

The number of images that can be seen depends on the angle between the object and the mirrors. If the object is placed perpendicular to the mirrors, then an infinite number of images will be formed. However, if the object is placed at an angle to the mirrors, then only a finite number of images will be visible.