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The Question

(Submitted March 07, 1997)

What are the respective wavelength and frequency ranges for the main six subdivisions of the electromagnetic spectrum (i.e gamma, x-rays, ultraviolet, visible, infrared, radio) and what is the name of the quanta of a gamma-ray?

The Answer

There are no "hard" numbers for the wavelengths/frequencies of the various parts of the electromagnetic spectrum. For example, what is considered a high-energy X-ray and what is considered a low-energy gamma-ray is very blurry. But here is a "ball park" guide:

Frequency Range (Hz) Wavelength Range Type of Radiation
10E20-10E24 10E-12 - 10E-16 m gamma-rays
10E17 - 10E20 1 nm - 1 pm x-rays
10E15 - 10E17 400 - 1 nm ultraviolet light
4.3 - 7.5x10E14 700-400 nm visible light
10E12 - 10E14 2.5 um - 700 nm infrared light
10E8 - 10E12 1 mm - 2.5 um microwaves
10E0 - 10E8 10e8 - 1 m radio waves

All quanta in the electromagnetic spectrum, regardless of its wavelength, is called a photon.

You can read more about the electromagnetic spectrum at:

Laura Whitlock
for the Ask an Astrophysicist Team

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