Characteristics of Electromagnetic Wave

An electromagnetic wave can be described using a handful of standard parameters. Wavelength, symbol $\lambda$ (the Greek letter lambda), is the distance between two consecutive crests (or two consecutive troughs) of the wave, measured in metres (m) as the SI unit. Frequency, symbol $\nu$ (the Greek letter nu), is the number of complete waves that pass a fixed point in one second, measured in hertz (Hz, i.e. s⁻¹). Wavenumber, symbol $\bar\nu$ ('nu bar'), is the number of wavelengths that fit into a unit length, related to wavelength by $\bar\nu = \frac{1}{\lambda}$; it is commonly expressed in reciprocal centimetres (cm⁻¹), though its SI unit is m⁻¹. Amplitude, symbol A, is the height of the wave's crest above its central axis; the square of the amplitude is a measure of the radiation's intensity. Different regions of the electromagnetic spectrum correspond to different frequency/wavelength ranges — radiofrequency radiation is around $10^6$ Hz, microwaves around $10^{10}$ Hz, infrared around $10^{13}$ Hz, and ultraviolet around $10^{16}$ Hz. In a vacuum every type of electromagnetic radiation travels at the same speed, …