The Electromagnetic Spectrum
Light is also measured using the electromagnetic spectrum. The electromagnetic spectrum is the range of all possible and known frequencies of electromagnetic radiation, which simply means energy that continues to spread out as it travels (The Imagine Team, 2013). The spectrum consists of low frequencies used for radio communication to gamma rays used in xrays (The Imagine Team, 2013). The part of the spectrum that is most sensitive to human beings’ eyes is classified as the visible spectrum (The Physics Classroom, 2013). The light that is actually visible to the human vision system makes up only a tiny portion of the visible spectrum. The visible spectrum ranges from the high frequency, small wavelength (ultraviolet) category of 400nm to the low frequency, large wavelength (infrared) category of 700 nm (Lidenfeld, 2011). Figure 3 below shows the electromagnetic spectrum including the visible spectrum: