Cambridge IGCSE Physics · Syllabus 0625 · Waves
Monochromatic light
What is Monochromatic light?
Visible light of a single frequency is described as monochromatic. Because it contains only one frequency it also has a single wavelength and a single colour, so a prism deviates all of it through the same angle and cannot disperse it into a spectrum.
This definition is part of the Waves chapter in Cambridge IGCSE Physics.
Examiner tips on Monochromatic light
- Answering “what does monochromatic mean?” Say light of a single frequency. “One colour” is the translation of the word, not the physics, and on its own it is unlikely to score. If the question then asks what happens when monochromatic light enters a prism, the answer is that it is refracted but not dispersed, because there is only one frequency to separate.