All electromagnetic waves travel at the same speed, but they have different wavelengths and different frequencies. The electromagnetic spectrum is the name for the range of electromagnetic waves when they are placed in order of increasing frequency. The diagram below shows the electromagnetic spectrum.

electromagnetic spectrum

Source: Adapted from Electromagnetic Spectrum, University of Arizona

As you can see from the diagram, radio waves are shown on the left as having the longest wavelengths and lowest energy and frequency. Moving from left to right (increasing in energy and frequency and decreasing in wavelength) are microwaves, infrared, visible, ultraviolet, x-rays, gamma rays, and cosmic rays.

Interactive exercise. Assistance may be required. Answer the following questions about what you can learn from the graphic.