Thin lenses. Arrows indicate direction of travel of light. Virtual rays are drawn as dashed lines.

Drag E to move and resize the object. Drag f_1 and f_2 to change the focal lengths types of lenses.[br][br]What happens when the object crosses the focal point? [br][br]What happens when the object gets tall compared to the lens?[br][br]When can you get a real image?