The electromagnetic spectrum refers to the entire range of electromagnetic waves, including both visible and invisible waves, ordered by their wavelengths or frequencies. It encompasses a broad range of wavelengths, from the extremely short wavelengths of gamma rays to the very long wavelengths of radio waves.
Light, on the other hand, specifically refers to the subset of electromagnetic waves that are visible to the human eye. It occupies a small portion of the electromagnetic spectrum, ranging from approximately 400 to 700 nanometers in wavelength. Light is responsible for our visual perception and is composed of different colors that can be seen in a rainbow.
Radiation, in the context of the electromagnetic spectrum, is a general term used to describe the emission and transmission of energy through electromagnetic waves. It encompasses all forms of electromagnetic waves, including light. So, light can be considered a type of radiation, but not all radiation is visible light. The term "radiation" is often used to describe electromagnetic waves across the entire spectrum, regardless of whether they are visible or not.
In summary, the electromagnetic spectrum refers to the full range of electromagnetic waves, while light refers specifically to the visible portion of the spectrum. Radiation is a broader term that encompasses all electromagnetic waves, including light.