Lens

How it is used

Converging lenses are also called convex lenses, and diverging lenses concave lenses. Lenses are used in cameras, glasses, microscopes and the human eye. Ray diagrams show where the image forms. The plural is 'lenses'.

Example sentences

1. A converging lens with a focal length of 10 cm forms a real image of the candle on the screen.

2. People who are short-sighted wear glasses with diverging lenses.

Common collocations

• converging lens
• diverging lens
• convex lens
• concave lens
• ray diagram

Related terms

• focal lengthThe distance from the centre of a lens or mirror to its focal point, where parallel rays of light meet or appear to come from. It is usually given in centimetres or metres.
• refractionThe change in direction of a wave as it passes from one material into another, caused by a change in its speed. It is why a straw looks bent in a glass of water.
• reflectionThe bouncing back of light, sound or another wave when it hits a surface. For a flat mirror, the angle of reflection equals the angle of incidence.
• electromagnetic spectrumThe full range of electromagnetic waves, ordered by wavelength or frequency: radio waves, microwaves, infrared, visible light, ultraviolet, X-rays and gamma rays.

This word in other fields

The same English word can have a different meaning in another field:

• lens · Photography

More terms: Light and Optics

• total internal reflection