What type of image is formed when the object is placed in front of F or focus in a convex lens?

There are six possibilities of position of object in the case of convex lens:

Table of Contents Show

Object at infinity:
Object at CCentre of Curvature
Object at Focus F1
Summary of Image Formation

Object at infinity:

Convex lens converge parallel rays coming from objet at infinity and a highly diminished - point sized, real and inverted image is formed at principal focus F2.

Fig: Object at Infinity

Properties of Image: Image is highly diminished, real and inverted.

A diminished, real and inverted image is formed between principal focus, F2 and centre of curvature, C2 at the opposite side when an object is placed beyond C1 of a convex lens.

Fig: Object Beyond 2F

Properties of Image: Image is diminished, real and inverted.

Object at CCentre of Curvature

A same sized, real and inverted image is formed at centre of curvature, C2 when object is placed at centre of curvature, C1 of a convex lens.

Fig: Object at 2F

Properties of Image: Image is same size as object, real and inverted.

An enlarged, real and inverted image is formed beyond centre of curvature, C2 when an object is placed between centre of curvature, C1 and principal focus, F1 of a convex lens.

Fig: Object between 2F and F

Properties of Image: Image is enlarged, real and inverted.

Object at Focus F1

An infinitely large, real and inverted image is formed at infinity when object is placed at principal focus, F1 of a convex lens.

Fig: Object at F

Properties of Image: Image is highly enlarged, real and inverted.

A virtual, erect and enlarged image is formed at the same side of lens, when an object is placed between principal focus, F1 and optical centre, O of a convex lens.

Fig: Object between F and O

Properties of Image: Image is enlarged, virtual and erect.

Summary of Image Formation

Object at Infinity	Image is formed at focus. Image is real, inverted and highly diminished in size.
Beyond C	Image is formed between F2 and 2F2. Image is real, inverted and smaller than object.
Between C and F	Image is formed beyond C2 or 2F2. Image is real, inverted and larger than object.
At C	Image is formed at 2F2 or C2. Image is real, inverted and of same size as object.
At F	Image is formed at infinity. Image is real, inverted and highly enlarged.
Between F and O	Image is formed on 2F1. Image is virtual, erect and larger than object.

Spherical lenses are lenses formed by connecting two spherical transparent surfaces. 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 lenses since the rays converge after falling on the convex lens. 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.

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

- When an object is placed at infinity, the real image is formed at the focus. The size of the image is highly diminished and point size.

- When an object is placed beyond the centre of curvature, the real image is formed between the centre of curvature and focus. The image size will not be the same as the object. It will be diminished in size..

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

- When an object is placed in between the centre of curvature and focus, the real image is formed behind the centre of curvature. The size of the image is larger than that of the object.

- When an object is placed at the focus, a real image is formed at infinity. The size of the image is much larger than that of the object.

- When an object is placed in between focus and optical centre, a virtual image is formed. The size of the image is larger than that of the object.

- When an object is placed at infinity, a virtual image is formed at the focus. The size of the image is highly diminished and point size.

- When an object is placed at a finite distance from the lens, a virtual image is formed between the optical centre and the focus of the convex lens. The size of the image is smaller than that of the object.

Put your understanding of this concept to test by answering a few MCQs. Click ‘Start Quiz’ to begin!

Select the correct answer and click on the “Finish” button
Check your score and answers at the end of the quiz

Visit BYJU’S for all Physics related queries and study materials

0 out of 0 arewrong

0 out of 0 are correct

0 out of 0 are Unattempted

View Quiz Answers and Analysis