At the outset of this course, we should go over make some basic material that you have probably covered at A-level or in the first year lab. This will be discussed fully in your course on electromagnetism. The speed at which these waves propagate is determined by the fundamental physical constants and . The part of the spectrum that we see as visible light lies somewhere in the middle.
Blue colours have shorter wavelengths than red colours.
Light is polarised, so that two distinct light waves may propagate in the same direction even if they have same frequency. Travelling waves may be represented as The sum is over the different frequencies. This leads to . The factor of cancels if we implicitly sum over the two polarisations of the wave. It is often easier to use the complex number representation and to then separate the real and complex parts at the end of the calculation.