Electromagnetic Wavelength
The variation of the electric and magnetic fields caused, for instance, by the alternating movement of electric charges is characterised by its wavelength. The visible light is a fraction of electromagnetic waves. Classified by ascending frequency, electromagnetic waves are called radio waves, microwaves, infrared waves, red waves, yellow waves, green waves, blue waves, violet waves, ultraviolet waves, X-rays, and gamma rays. In vacuum, they travel at light speed, c.