Concave and Convex lens

Concave lens: The polar opposite of a convex lens, a concave lens causes parallel light beams to curve outwardly or diverge. Concentric lenses are also known as diverging lenses as a result of this. The distinction between concave and convex lenses becomes clear when considering the concave lens internally.

Convex lens: A convex lens (also known as a positive lens) has glass (or plastic) surfaces that protrude outwardly at the centre. A convex lens is also known as a converging lens because the parallel light rays travelling through it curve inward and meet (converge) at a point directly beyond the lens known as the focal point.

Differences between concave and convex lenses

Types of concave lens

There are three different types of concave lenses:

Bi-Concave: Bi-concave lenses, also known as double-concave lenses, have the same radius of curvature on both sides and diverge collimated incident light in the same way that plano-concave lenses do.

Plano-Concave: A plano concave lens has one concave surface and one flat surface and has a negative focal length.

Convexo-Concave : A convexo-concave lens’ convex face has a lesser curvature than its concave face, therefore the former is always moving away from the latter.

Types of convex lens

There are three types of convex lenses:

Biconvex lens : Simple biconvex lenses consist of two convex spherical surfaces with the same curvature radius.

plano-convex lens : These lenses feature a positive focal length and one spherical and one flat surface. They’re designed for applications that don’t require a lot of conjugate (parallel light) imaging.

concavo-convex lens : When viewed from one side, a concavo convex lens is convex, and when viewed from the other side, it is concave. A biconvex lens focuses a beam of light from objects that are further away from its focal point.

Image formation by concave convex lens

Convex lens 

• When an object is positioned at infinity, the true image is formed at the focus. The image is a tiny representation of the real object.

• When an object is positioned behind the centre of curvature, a true picture is generated between the centre of curvature and the focus. The image is the same size as the object when compared to its size.

• When an object is at the centre of curvature, the true picture of it is formed at the other centre of curvature. The image is the same size as the object when compared to its size.

• A real image is created behind the centre of curvature when an object is put between the centre of curvature and the focus. The image is significantly larger than the object.

• When an object is placed on the focus, a real image is created at infinity. The image is a lot bigger than the real object.

•When an object is placed between the focus and the pole, a virtual image is formed. The image is a lot bigger than the object.

Concave lens

• A virtual image is produced at the focus when an object is positioned at infinity. The image is only a fraction of the real object’s size.

 •When an object is positioned at a finite distance from the lens, a virtual picture is created between the pole and the focus of the convex lens. The image is significantly larger than the object.

Uses of concave convex lens

Concave lens

1.Concave lenses are used to correct myopia (short-sightedness).

2.Concave lenses are used in flashlights to magnify the light generated by the bulb.

3.Used in peepholes on house doors to provide security by allowing a view of individuals or objects outside the doors.

Convex lens

1.It is used in spectacles to treat hypermetropia, or long sightedness, a vision condition.

2.It was used to construct a simple camera.

3.It has served as a magnifying glass.

4.It can be found, among other things, in microscopes, telescopes, and movie projectors.

Conclusion 

Thin lenses are optical devices that bend light in a number of different directions. Convex lenses focus distant images at a point on the opposite side of the lens from the light source. When parallel beams of light pass through a convex lens, the refracted rays converge at a single point called the primary focus. Concave lenses focus distant objects so that someone standing on the opposite side of the lens from the incident light sees them as if they were behind the lens. The refracted rays diverge as parallel light beams pass through a concave lens, creating the appearance of coming from a single point called the primary focus.