How a concave lens forms a virtual image

Here you have another principal ray diagram, just like the one we constructed on the previous page, only this one is interactive. You can click on the object and drag it, and observe what happens to the image. Notice that, as we saw on the previous page, this image is a virtual image. To remind you of this, it is shown striped. "Virtual image" means that the light rays are not actually coming from the position where the virtual image is located – nothing is really there. But the light rays emerge from the lens *as if* they were coming from the virtual image. Move the object back and forth to see what happens to the image. As you can see, a concave lens always produces an upright, reduce, virtual image.

 

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