Ray diagram of convex lens when object is at focus (F1)

In this post, we will draw a convex lens ray diagram when the object is placed at the focus point (`F_1`)

Through this convex lens ray diagram, we can easily find the nature, position, and size of the image.

Steps of drawing a ray diagram of a convex lens

1. Draw the diagram of a convex lens

2. Place the object in the given position

3. Draw a ray diagram by following the rules

 

 

Draw the diagram of a convex lens

First of all, we will have to draw the diagram of a convex lens with a principal axis (a horizontal line passing through the optical center). Now mark `F_1` and `2F_1` on the left-hand side of the lens and `F_2` and `2F_2` on the right-hand side of the lens.

 

Place the object in the given position

Now we place the object at the focus point (`F_1`)

 

Draw a ray diagram by following the rules

With the help of rules for the formation of the image. We draw two light rays coming from point A.

The first light ray parallel to the principal axis incident on the convex lens and passes through `F_2` after refraction.

The second  light ray passes through the optical center (O) and goes straight without refraction.

Both the rays go parallel and seem to meet at infinity.

So, the image is formed at infinity

 

Position of image	At infinity
Nature of image	Real and inverted
Size of image	Enlarged

 

Related Topics

Image formation by a convex lens when 

1. When an object at infinity

2. When an object beyond 2F1

3. Object between 2F1 and F1

4. Object at 2F1

5. Object between F1 and O

6.  What is a refractive index