c = speed of light = 3 x 10^{10} cm/sec = 3 x 10^{8} m/sec h = Planck's constant = 6.626 x 10^{-34} J/sec

c = wavelength x frequency

energy of a photon = h x frequency

nano means "billionth": 1 nm = 1 x 10^{-9} m OR 1 x 10^{9} nm = 1 m mega means "million": 1 x 10^{6} Hz = 1 MHz Frequency refers to the number of waves that pass by each second and is measured in a unit called Hertz (Hz).