(1) Transfer of heat through electromagnetic waves from hot to cold.(2) Electromagnetic waves of energy having frequency and wavelength. The shorter wavelengths (higher frequencies) are more energetic. The electromagnetic spectrum is comprised of (a) cosmic rays, (b) gamma rays, (c) x-rays, (d) ultraviolet rays, (e) visible light rays, (f) infrared, (g) microwaves and (h) radio waves