Electromagnetic spectrum
ScienceDefinition
The electromagnetic spectrum is the complete range of electromagnetic radiation, from the longest wavelength radio waves to the shortest wavelength gamma rays. All electromagnetic waves travel at the speed of light in a vacuum but differ in wavelength and frequency.
Examples
- Microwaves in your kitchen use specific EM frequencies to heat water molecules in food
- X-rays have short wavelengths that can pass through soft tissue but are absorbed by bones
- Visible light (400-700 nm) is the only part of the EM spectrum humans can see
Key Fact
Order from longest to shortest wavelength: Radio > Microwave > Infrared > Visible > Ultraviolet > X-ray > Gamma. c = λf (3 × 10⁸ m/s).
Study This Concept
Practice electromagnetic spectrum with free review games in these units: