Electromagnetic Spectrum

All electromagnetic waves are transverse waves that travel at $3.0 \times 10^8$ m/s in a vacuum. They differ in wavelength and frequency.

In order of decreasing wavelength: radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, gamma rays.

All electromagnetic waves transfer energy, can be reflected, refracted and diffracted, and do not need a medium. Higher-frequency waves (UV, X-rays, gamma) carry more energy per photon and are more hazardous to living tissue.