A lens is a transmissive optical device that focuses or disperses a light beam by means of refraction. Lenses are made from materials such as glass or plastic, and are ground and polished or molded to a desired shape. A lens can focus light to form an image, unlike a prism, which refracts light without focusing.

Optical principles for lenses. A lens produces its focusing effect because light travels more slowly in the lens than in the surrounding air, so that refraction, an abrupt bending, of a light beam occurs both where the beam enters the lens and where it emerges from the lens into the air.

Lenses serve to refract light at each boundary. As a ray of light enters a lens, it is refracted; and as the same ray of light exits the lens, it is refracted again. Because of the special geometric shape of a lens, the light rays are refracted such that they form images.

English Language Learners Definition of lens : a clear curved piece of glass or plastic that is used in eyeglasses, cameras, telescopes, etc., to make things look clearer, smaller, or bigger. : the clear part of the eye that focuses light to form clear images.

There are two types of lensesconvex and concave. Convex lenses are lenses that curve outwards, they converge parallel light rays to a focal point. Concave lenses are thinner in the middle and thicker at their edges. Concave lenses diverge parallel light rays away from each other. Hope this helps u.

where u is the distance of the object from the lens; v is the distance of the image from the lens and f is the focal length, i.e., the distance of the focus from the lens.

What is the difference between Real and Virtual Image?…Difference between Mirror and Lens.

A dioptre (British spelling) or diopter (American spelling) is a unit of measurement of the optical power of a lens or curved mirror, which is equal to the reciprocal of the focal length measured in metres. (1 dioptre = 1 m−1.) It is thus a unit of reciprocal length.

The optical power of a healthy human eye is about 40 diopters, meaning the ability to focus on an object or image 1/40 of a meter from the eye. The eye of a typical young person can adjust an additional 20 diopters. By age 25 this focusing flexibility is usually reduced to about 10 diopters.

This refers to the amount of curvature a lens will have. More curvature means a thicker lens, more magnification and a higher diopter number. For example, if you’re looking at a 3-diopter lens, it’s magnification = ¾ + 1… or . 75 + 1 = 1.75x. Objects viewed under a 3 diopter lens will appear 175% bigger than normal.

If a lens has a shorter focal length it is said to be more powerful. The power of a lens is defined as the reciprocal of the focal length. Lens power is measured in dioptres (D).

It is. a concave lens of focal length 5 m.

Solution. Negative sign indicates it is a diverging lens. Therefore, the lens is concave in nature.

The nature of a lens having a power of + 0.5 D is Convex lens.

A converging lens is a lens that converges rays of light that are traveling parallel to its principal axis. Converging lenses can be identified by their shape; they are relatively thick across their middle and thin at their upper and lower edges.

Also known as divergent lens, negative lens, concave lens or dispersive lens. A lens that causes parallel light rays to spread out – hence diverge – away from the optical axis once exiting the lens. The edge of a diverging lens is always thicker than the center. …

Concave lens is called a diverging lens. The working of the lens is dependent on the refraction of the light rays as they pass through the lens. Concave lens is used to magnify images in telescopes and binoculars.

The concave lens is a diverging lens, because it causes the light rays to bend away (diverge) from its axis. In this case, the lens has been shaped so that all light rays entering it parallel to its axis appear to originate from the same point, F, defined to be the focal point of a diverging lens.

A convex lens or converging lens focuses the light rays to a specific point whereas a concave lens or diverging lens diverges the light rays. When these lenses are combined, they produce sharper images. ….