Again, the full range of frequencies extends beyond the visible spectrum, from less than one billion Hz, as in radio waves, to greater than 3 billion-billion Hz, as in gamma rays. As noted above, light waves are waves of energy. Thus gamma rays have the most energy, and radio waves have the least. Of visible light, violet has the most energy and red the least. Light not only vibrates at different frequencies, it also travels at different speeds.
Light waves slow down when they travel inside substances, such as air, water, glass or a diamond.
The way different substances affect the speed at which light travels is key to understanding the bending of light, or refraction, which we will discuss later. So light waves come in a continuous variety of sizes, frequencies and energies. Figure 2 is not drawn to scale, in that visible light occupies only one thousandth of a percent of the spectrum. Inc. All rights reserved. Simply register for a free Postbox in the country where your merchant is located.