(EMR) Electromagnetic radiation consists of an electric and a magnetic field component. All EMR travels in a vacuum at the speed of light. EMR is classified related to the frequency//length of the wave.
An EM wave consists of discrete packets of energy, named photons (quantization). The energy of the photons depends on the frequency of the wave. Planck-Einstein equation: E = h * f
E (energy); h (Planck's constant); f (frequency)
EMR types include in order of increasing frequency//decreasing wavelength: radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, x-rays and gamma rays. EMR contains energy and momentum, which may be imparted when it interacts with matter.
See Gamma Radiation.