spectrum

Click a letter for the index

Or search the encyclopaedia:

 

 

Go

 

Click images to enlarge
In physics, the pattern of frequencies or wavelengths obtained when electromagnetic radiations are separated into their constituent parts. Visible light is part of the electromagnetic spectrum and most sources emit waves over a range of wavelengths that can be broken up or ‘dispersed’; white light can be separated (for example, using a triangular prism) into red, orange, yellow, green, blue, indigo, and violet. The visible spectrum was first studied by English physicist Isaac Newton, who showed in 1666 how white light could be broken up into different colours.

The Star of David is a centuries-old symbol of Judaism. Blue and white are traditional Jewish colours. Effective date: 21 November 1948. >>