LENSES

CONVERGING LENSES

• Converging lenses are lenses that converge rays of light that travel parallel to its principal axis.
• They can be identified by their shape.
• They are thick across their middle and thin at their upper and lower edges.

DIVERGING LENSES

• Diverging lenses are lenses that diverge rays of light that travel parallel to its principal axis.
• They also can be identified by their shape.
• They are thin across their middle and thick at their upper and lower edges.

RAY DIAGRAMS FOR LENSES

RAY DIAGRAMS FOR CONVEX LENSEs

• For objects outside the focal point, a real inverted image will be formed.
• For objects inside the focal point, a virtual image will be formed.

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RAY DIAGRAMS FOR CONCAVE LENS

• Inside and outside the focal point give the same results.
• An erect virtual image is smaller than the object.
• The image is always formed inside the focal length of the lens.

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RAY DIAGRAMS FOR TWO LENSES

• The principal rays 1 and 2 show the location of the of the image for lens 1 alone.
• Ray 3 through the point f1 goes towards lens 2 parallel to the axis and will project through focal point f2, forming one principal ray 4 for the final image.
• Lens 2 will define the second needed ray 5 since that ray will be undeflected.

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Sources

• France, Dr. Colin. "GCSE PHYSICS - Ray Diagram for an Image Made by a Convex Lens - What Is a Real Image? - What Is an Inverted Image? - GCSE SCIENCE." GCSE PHYSICS - GCSE SCIENCE. Web. 7 May 2015.
• Nave, R. "Ray Diagrams for Lenses." HyperPhysics Light and Vision. HyperPhysics. Web. 7 May 2015. .