What is the principle of marginal rays in optics?

The principle of marginal rays in optics states that the outermost rays of a beam define the limits of the image.

When light passes through an optical system, it is refracted by the lenses or mirrors. The principle of marginal rays is used to determine the size and position of the image formed by the system. According to this principle, the outermost rays of a beam are the ones that pass through the edges of the lens or mirror, and they define the limits of the image. These rays are called marginal rays.

The marginal rays are important because they determine the size of the image. If the marginal rays are not focused properly, the image will be blurred or distorted. Therefore, optical systems are designed to ensure that the marginal rays are focused correctly. This is achieved by adjusting the shape and position of the lenses or mirrors.

The principle of marginal rays is used in many optical systems, including cameras, telescopes, and microscopes. By understanding this principle, we can design and build optical systems that produce clear and accurate images.