10 Difference Between Convex And Concave Lens (With Examples)

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Convex Lens

If a piece of glass or other transparent material takes on the appropriate shape, it is possible that parallel incident rays would either converge to a point or appear to be diverging from a point.  Therefore, a transmissive optical device that focuses or disperses a beam of light by means of refraction is referred to as a lens.

A convex Lens also known as a converging lens is a lens that converge rays of light that are travelling parallel to its principal axis. The edges of a convex lens are curved outward rather than inward. A convex lens bends light rays inward, which results in the object being perceived as larger or closer. More importantly, they are thick across the middle and thin at the upper and lower edges. Given that convex lens have a curved surface, light rays falling on the surface will refract to different direction.

What You Need To Know About Convex Lens

  • Convex lens are lens which merges the light rays at a particular point that travels through.
  • A convex lens is thicker at the middle and thinner at the edges.
  • Convex lens forms a real image, but it can also create a virtual image when the object is in the middle and optical center.
  • In the convex lens, the curve is facing outward.
  • In convex lens, the focal length is positive
  • Convex lens due to thickness of the centre, the object will appear closer and larger.
  • The position of focal point in convex lens is in front of the lens.
  • When light rays passes through the convex lens, it converges the light rays and focuses on one point.
  • In convex lens, both the image and the object are on the same side of the lens unlike concave lens.
  • Convex lenses are used to rectify the problem of farsightedness (hyperopia).

Some examples of objects with convex lenses in include:

  • Binoculars and telescopes
  • Cameras
  • Eye glasses
  • Flashlights
  • Lasers ( CD, DVD players)

Concave Lens

Concave lens or diverging lens is a lens that diverge rays of light that are travelling parallel to its principal axis. Diverging lens can also be identified by their shape; they are relatively thin across their middle and thick at their upper and lower edges.

What You Need To Know About Concave Lens

  • Concave lens, are lens which disperses or diverges the light rays passing through it.
  • Concave lenses are thinner at the middle and thicker at the edges.
  • The image formed by the concave lens is upright, virtual and smaller than the object.
  • In the concave lens, the curve faces inward.
  • In concave lens the focal length is negative.
  • Concave lens due to thinness of the centre, the object will appear smaller and beyond.
  • Position of the focal point is on the back side of the lens.
  • When light rays go through the concave lens, it disperses, making them to spread out to different direction.
  • The object is on one side of the lens while the image is on the other side.
  • The concave lenses are used to rectify the problem of shortsightedness (myopia).

Examples of where concave lens are used:

  • Used as a side-view mirror on the passenger and drivers side of a car.
  • Used for security purposes in supermarkets and building apartments.
  • Used to make lenses of sunglasses.

Also Read: Difference Convex And Concave Mirrors

Difference Between Convex Lens And Concave lens In Tabular Form

Elements of Comparison Convex Lens Concave Lens
Description Convex lens are lens which merges the light rays at a particular point that travels through. Concave lens, are lens which disperses or diverges the light rays passing through it.  
Structure A convex lens is thicker at the middle and thinner at the edges. Concave lenses are thinner at the middle and thicker at the edges.  
Image Formation Forms a real image, but it can also create a virtual image when the object is in the middle and optical center. The image formed by the concave lens is upright, virtual and smaller than the object.  
The Curve The curve is facing outward. The curve faces inward.
The Focal Length The focal length is positive The focal length is negative.  
Object Convex lens due to thickness of the centre, the object will appear closer and larger. Concave lens due to thinness of the centre, the object will appear smaller and beyond.  
Position of the focal point The position of focal point in convex lens is in front of the lens. The position of the focal point is on the back side of the lens.  
Light Rays When light rays passes through the convex lens, it converges the light rays and focuses on one point. When light rays go through the concave lens, it disperses, making them to spread out to different direction.
Position of Image Both the image and the object are on the same side of the lens. The object is on one side of the lens while the image is on the other side.  
Real Life Applications Convex lenses are used to rectify the problem of farsightedness (hyperopia). The concave lenses are used to rectify the problem of shortsightedness (myopia).  
Example of Objects that uses the Lens Some examples of objects with convex lenses in include:
Binoculars and telescopes
Cameras
Eye glasses
Flashlights
Lasers ( CD, DVD players)  
Examples of where concave lens are used:
Used as a side-view mirror on the passenger and drivers side of a car.
Used for security purposes in supermarkets and building apartments.
Used to make lenses of sunglasses.  

Summary

Convex lens are lens which merges the light rays at a particular point that travels through while concave lens, are lens which disperses or diverges the light rays passing through it.