Moving the object further from the lens gives the following ray diagram.

As you can see, moving the object further from the lens causes the image to move closer to the lens and become smaller. If we move the object further and further away, the image will get smaller and smaller. The image's location will move closer and closer to the focal point. If the object were very very far away, like the sun, then the light would be focused to a point - the focal point.

Moving the object closer to the lens gives the following ray diagram.

Clearly, moving the object closer to the lens makes the image become both larger and further away. As you move the object closer and closer to the focal point, the image will become further and further away.

Let us try moving the object still closer to the lens. (We will have to make the object smaller in height so that we can get the image on the screen.)

As expected the image moves further away and becomes much bigger than the object.

We know from before that if the object were right at the focal point, the rays would come out horizontally and the image would be in some sense infinitely far away.

## Question

What happens when we move the object inside the focal point?

Selman Hershfield / selman@phys.ufl.edu