text: Electromagnetic radiation is a form of energy that occurs in waves. As such, different types have different wavelengths and frequencies. The highest energy (smallest wavelength and greatest frequency) is Gamma rays. Next is infrared rays. Decreasing in energy, next is ultraviolet rays. Then comes the range of light that we can see, called accordingly, visible light. With lower energy than that is microwaves and radio waves which have the longest wavelengths and shortest frequencies.