1. Here, we’ll show you how to draw a ray diagram for a convex lens when the object is between the focal point, F and the lens

2. Here is a diagram showing the location of the object, between the focal point and the lens. We’ll use a yellow arrow for the object. xxx F2F F The object is between the the F point and the lens

3. We’ve drawn this object so that the bottom of the object is sitting on the principal axis. xxx F2F F The bottom of the object is on the principal axis

4. We’ll start by drawing a straight line from the top of the object to the center of the lens, like this (click). This line must be parallel to the principal axis. xxx F2F F

5. Now we extend this line straight through the focal point on the right side of the lens like this (click). xxx F2F F

6. Next, we draw a straight line from the top of the object, through the middle of the lens, like this (click). xxx F2F F

7. Notice that in this case, these two rays are moving away from each other, or diverging. They will not cross each other. xxx F2F F These two rays will not cross each other

8. Therefore, no real image can be formed in this case. xxx F2F F These two rays will not cross each other No real image is formed

9. But if we extend this purple line backward, with a dotted line like this, (Click) xxx F2F F

10. And the green line backward with a dotted line, like this (click) xxx F2F F

11. They will cross right at this point. xxx F2F F They cross at this point

12. Now let’s pretend we’re looking through the lens from the right side, xxx F2F F

13. When we see light rays, our brain assumes that they are travelling in straight lines from an object, xxx F2F F Our brain assumes that these two rays are travelling in straight lines from the object

14. so it appears like these two rays from the top of the object are coming straight from the point where these two dotted lines cross. xxx F2F F It appears like rays from the top of the object are coming straight from this point.

15. So this is where the top of the image will appear xxx F2F F The top of the image

16. And because the bottom of the object is sitting on the principal axis. xxx F2F F The bottom of the object is sitting on the principal axis The top of the image

17. The bottom of the image will also be on the principal axis, (click) right here directly underneath the top. xxx F2F F The bottom of the image will be here on the principal axis The top of the image

18. So we can draw the image here (click). xxx F2F F The top of the image The bottom of the image will be here on the principal axis

19. Because the actual rays, shown by the solid purple and green arrows do not actually cross,(click) xxx F2F F These two rays will not cross each other

20. this is not a real image. xxx F2F F This is NOT a real image These two rays will not cross each other

21. But it does appear to an observer, so it’s called (click) a virtual image. We show it here with a dotted outline. xxx F2F F A VIRTUAL image

22. To review, we see that when the object is between the focal point and the lens, the image is larger than the object, xxx F2F F The image is larger than the object, it is NOT inverted, and it is on the same side of the lens as the object object

23. It is not inverted, but right side up. xxx F2F F The image is larger than the object, it is NOT inverted, and it is on the same side of the lens as the object object

24. And its on the same side of the lens as the object. xxx F2F F The image is larger than the object, it is NOT inverted, and it is on the same side of the lens as the object object

25. And remember, this is a virtual, rather than real image. xxx F2F F A VIRTUAL image object