The purpose of this article is to understand the concave lens. You will also find much other important information that you need to know. For a better understanding of the concave lens, we will go through some practical applications where the concave lens is very useful.

Introduction

Humans have been able to do some pretty amazing things with lenses for years. As people learned that they could do a variety of tasks using variously shaped lenses, the ways and purposes in which lenses were employed started to expand over the centuries. They might be used to make little objects appear larger and hazy objects appear clear, in addition to making distant objects seem closer (like the telescope). Two fundamental lens types are used to do these tasks: convex and concave lenses. A lens is referred to as concave if at least one of its surfaces curves inward. It is a divergent lens, which means that light rays that have been bent through it are spread out.

Terminology related to lens

Pole

For the spherical lens pole (p) is the center or middle point of the lens.

Center of curvature

Generally spherical lenses is cut from a sphere. So the center of curvature is the sphere’s center, from where the mirror is made.

Main axis

These are the lines that cross the lens’s pole and its center of curvature.

The principal focus

It is the location at which a converging or diverging narrow beam of light occurs.

Focal length

The distance between the focus and the mirror’s poles is known as the focal length (f).

Image formation by a concave lens

The image formation by a concave lens is summarized below.

The object placed at infinity

When an object is placed at infinity the image is formed at the focus of the lens. It will be virtual and a point-size image.

Fig- 1

The object placed between the optical center O and the infinity

When the object is placed at a finite distance between the optical center and infinity the image forms at the first focus. The size of the image is smaller than the real object and it is virtual.

Fig- 2

Some important formulas of the concave lens

Lens formula

The type and location of the image created by the concave lens are determined using the lens formula. The lens formula looks like the following

Here, f = focal length of lens

v = distance of the image from the optical center

u = distance of the object from the optical center

Magnification formula

The magnification formula shows how big the image is formed in comparison of a real object.

Magnification, =

Application of concave lens

The concave lens has a wide area of application. Some of them are the following

• In telescopes and binoculars, concave lenses are used to magnify objects.
• Myopia, is most frequently treated with concave lenses.
• Security tools like peepholes or door viewers provide a comprehensive view of everything beyond walls or doors. To reduce the size of the items and provide a wider view of the object or region, a concave lens is utilized.

Recommended Articles:

Compressive Stress: Introduction, Unit, formula, Dimension And Strength
Compton Wavelength: Introduction, Equation, Importance, And Effect
Concave And Convex Mirrors Spherical Mirrors
Concave Convex Lenses: Introduction, Difference, And Applications
Concave Mirror And Convex Mirror: Introduction, Types, Difference, And Applications