Concave Lens

Introduction:

Concave lens is one of the types of lenses. It seems like the lens curved inwards and it is not widely used among people.

What is concave lens?

Concave lens also called diverging lens and sometimes known as negative meniscus lens because there is no real images formed in this lens.

Basics of concave lens:

• Principal axis: It is the straight line drawn through the midpoint of the lens on both the directions.
• Focal point: In concave lens, the light ray whether it is parallel to principal axis or non-parallel to principal axis, it diverges away from the lens, so there is no chance of meeting (convergence) of light rays after refraction. If you trace backwards the diverged light rays as the imaginary lines, then there is a chance of meeting of such imaginary lines. The meeting point of such lines is considered as focal point. Here, focal point represented in the side of the object, not in the side of image.
• Focal length: The distance between the focal point and the midpoint is considered as the focal length of concave lens.

Lens equation:

The equation of the concave lens is almost same as that of convex lens but there is some difference to represent it. 1/u +1/v =1/f

Where,

'u' represents object distance

'v' represents image distance

( the value of 'v' should be represented in minus or it is found as negative value )

'f' represents focal length

( the value of 'f' should be represented in minus or it is found as negative value).

Let us know the possibilities of image formation, image position for concave lens.

There are only two possibilities of the image formation by the concave lens, because it is diverging lens.

Uses:

• Used to correct myopia
• Used in combination with convex lens to correct chromatic aberration and spherical aberration.