Properties of Lenses

Find out graphically what the properties of converging and diverging lenses are. As you might know from light refraction in general, light is refracted at interfaces. If light strikes a lens, no matter if converging or diverging lens, light gets always refracted at the inferface of air-glass-air, as you can see in this depiction.

In the picture you can see, drawn in red, the course of a light ray. This representation would be the physically correct one. The refraction actually happens at both surfaces. But to make things easier the refraction is only represented as if it happened at the centre plain of the lens.
The optical axis runs through the centre point M of the lens. The optical axis and the centre plain are at right angles to each other. One fixed property every lens has is its focal distance f. This distance depends on the degree of the lens's curvature. The focal distance is the distance between the centre point of the lens and its focal points F.
By clicking on the arrow you will move on to the next page. There you can track the course of a light ray in converging and diverging lenses all by yourself.