Geometrical Optics

Geometrical Optics Notes for Class 11 - 12

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Optical path

The path traversed by light in a vacuum at a particular time which is taken by the light to travel a particular distance in any other medium is called an optical path.

Fermat's Principle

When a light ray traverses from one point to other after reflection or refraction it follows a path whose distance will be either maximum or minimum and the time that will be taken for this will be maximum or minimum.

Power of lens

The ability of a lens to converge or diverge a bundle of light rays is called the power of a lens.

The power of a lens having a one-meter focal length is called one diopter. The power of a lens is inversely proportional to its focal length.

Angular magnification

Angular magnification is defined as the ratio of the visual angle produced in the eye by the image of an object formed by a visual instrument to the visual angle produced in the eye directly by the object.