Wavelengths Between Red and Violet

Look carefully at the diagram at the top of the page. Now check out the following questions (and answers)!

1. Is visible light a form of electromagnetic radiation?
2. Do different wavelengths of light correspond with different colours seen by an observer?
3. What is the unit of measurement for wavelengths of visible light?
4. What is the name of the invisible band of wavelengths next to red?
5. Name two colours with the long wavelengths?

Introducing the diagram! Read back and forward between the image at the top of the page and the explanation below!

This diagram is about which wavelengths of electromagnetic radiation correspond with the different colours we see in the world.

It shows that whilst the visible spectrum often appears to an observer to be made up of six bands of colour, every wavelength between 700 and 380 nanometres corresponds with a different colour.

The scale along the bottom of the diagram is marked in nanometres with the corresponding colours shown above.

Remember that:

• Objects appear to be different colours to an observer depending on the wavelengths they reflect.
• The name given to light that contains all wavelengths of the visible spectrum is white light.
• When all wavelengths contained in white light reflect off a neutral coloured surface then the object appears white to an observer.
• When one or several bands of wavelengths reflect off a neutral coloured surface then the object appears coloured to an observer.
• The colour an observer sees depends on the wavelengths of visible light emitted by a light source and on which of those wavelengths are reflected off an object.
• Although a human observer can distinguish between many thousands of wavelengths of light in the visible spectrum our brains often produce the impression of bands of colour.