Light is a little different from sound waves, water waves and
string waves, because it can move through a vacuum. In general, the
velocity of light is constant, c = 3.00 x 108 m/s. So for
light, wavelength λ and frequency ν are related by
c = λν
Light is called electromagnetic radiation, which
basically means that it radiates (travels) and the wave part is
oscillating electric and magnetic fields. You don't need to worry
about the details of this now. The properties of different types of
light depend on their wavelength. X-rays used in medicine have very
short wavelengths and high frequencies; UV (ultraviolet) light gives you sunburns
and helps you make vitamin D, visible light is normal light, IR
(infrared) is used for night-vision goggles, microwave is used in
cooking, and radio is used in radios.
created by
Victor Blacus, via Wikimedia Commons
