On completion of this lesson, students should be able to:
The phenomenon of bending of light as it passes from one medium to another medium is called refraction of light. The refraction is caused due to change in velocity of light as it passes from one medium to another medium. This note contains different definitions regarding a lens and also shows how light bends when it passes through concave or convex lens.
The instrument, which are used to produce an image of an object by using a lens or a combination of lenses, are called optical instrument. Examples are a Photographic camera, microscope, telescope, etc. This note explains the normal working mechanism of telescope and microscope and briefly explains about the photographic camera: is an optical instrument that is used to record a permanent image of an object on a photographic film.
Conjunctive, ciliary body, aqueous, iris, cornea, pupil, lens, optic nerve, macula, retina, sclera, vitreous, etc. are the parts of human eye. This note has information about, the working principle of human eye and also the defects arise when the proper focus of light is not at the retina.
Magnification of a lens is defined as the ratio of the height of the image to the height of the object. The images can be of two types. An image that can be obtained on a screen is called a real image. An image which cannot be obtained on a screen is called a virtual image.