Concave And Convex Lenses: Image Formation

Spherical lenses are the lenses formed by bounding two spherical transparent surfaces together. In general there are two types of spherical lenses. So, lenses formed by binding two spherical surfaces bulging outward are known as convex lenses while the lenses formed by binding two spherical surfaces such that they are curved inward are known as concave lenses. This is one of the basic difference between concave and convex lenses.

Convex lenses are also known as converging lens since the rays converge after falling on the convex lens while the concave lenses are known as diverging lenses as the rays diverge after falling on the concave lens. In this article, we will learn about image formation by concave and convex lenses.

Concave And Convex

Guidelines for rays falling on the concave and convex lenses

  1. When a ray strikes concave or convex lenses obliquely at its pole, it continues to follow its path.
  2. When a ray, parallel to principal axis strikes concave or convex lenses, the reflected ray passes through a focus on the principle axis.
  3. When a ray, passing through focus strikes concave or convex lenses, the reflected ray will pass parallel to the principal axis.

Image Formation by Concave and Convex Lenses:

Convex Lenses

    • When an object is placed at infinity, the real image is formed at the focus. The size of the image is much smaller as compared to that of the object.

Concave And Convex

    • When an object is placed behind the center of curvature, the real image is formed between the center of curvature and focus. The size of the image is same as compared to that of the object.

Concave And Convex

    • When an object is at the center of curvature, the real image is formed at the other center of curvature. The size of the image is same as compared to that of the object.

Concave And Convex

    • When an object is placed in between the centre of curvature and focus, the real image is the formed behind the center of curvature. The size of the image is smaller as compared to that of the object.

Concave And Convex

    • When an object is placed at the focus, a real image is formed at infinity. The size of the image is much larger as compared to that of the object.

Concave And Convex

    • When an object is placed in between focus and pole, a virtual image is formed. The size of the image is larger as compared to that of the object.

Concave And Convex

Concave Lenses

    • When an object is placed at infinity, a virtual image is formed at the focus. The size of the image is much smaller as compared to that of the object.

Concave And Convex

    • When an object is placed at a finite distance from the lens, a virtual image is formed between pole and focus of the convex lens. The size of the image is smaller as compared to that of the object.

Concave And Convex

Summary of Image Formation by Concave and Convex Lens

Image formation by Concave Lens

Object Location

Image Location

Image Nature

Image Size

Infinity

At F2

Virtual and Erect

Highly Diminished

Beyond Infinity and Zero

Between F1 and Optical centre

Virtual and Erect

Diminished

Image formation by Convex Lens

Object location

Image location

Image nature

Image size

Infinity

At F2

Real and Inverted

Diminished

Beyond 2 F1

Between 2F2 and F2

Real and Inverted

Diminished

Between 2F1 and F1

Beyond 2F2

Real and Inverted

Enlarged

At F1

At infinity

Real and Inverted

Enlarged

At 2 F1

At 2F2

Real and Inverted

Same size

Between F1 and 0

On the same side as the object

Virtual and Erect

Enlarged

Stay tuned with BYJU’S to learn more about image formation by concave and convex lenses and explore more on physics formulas and calculators.

1 Comment

  1. I need this very much

Leave a Comment

Your email address will not be published. Required fields are marked *