Wavelengths of the Electromagnetic Spectrum
The electromagnetic spectrum is one continuous range of wavelengths. Know the order, the rough sizes, and the fact that shorter wavelength means higher frequency and higher energy.
Key Facts to Memorize
Radio
Longest wavelengths: about 1 mm up to kilometers.
Microwave
About 1 mm to 1 m.
Infrared
About 700 nm to 1 mm.
Visible light
400–700 nm. Violet is short, red is long (ROYGBIV runs long to short backwards).
Ultraviolet
About 10–400 nm.
X-ray
About 0.01–10 nm.
Gamma
Shorter than 0.01 nm — highest energy.
Key equations
c = λν with c = 3.00 x 10⁸ m/s, and E = hν with h = 6.626 x 10⁻³⁴ J·s.
Al says…
Remember the order with 'Raging Martians Invaded Venus Using X-ray Guns': Radio, Microwave, Infrared, Visible, Ultraviolet, X-ray, Gamma.
Practice This Topic
External Tools
- Blooket review game
Coming soon — Mrs. Cauthron will post the game link here.
- NASA: Introduction to the EM spectrum
Short, readable pages for each region.