Which term describes the complete set of wavelengths and frequencies of electromagnetic radiation?

• A. Electromagnetic radiation
• B. Wavelength
• C. Frequency
• D. Electromagnetic spectrum

Answer: (D)

The complete set of wavelengths and frequencies of electromagnetic radiation is described by the electromagnetic spectrum. This term groups all forms of EM radiation—from radio waves with very long wavelengths to gamma rays with extremely short wavelengths—into a continuous range. It helps explain how different forms of radiation differ in energy and interactions with matter, since a photon's energy scales with frequency (E = h f) or inversely with wavelength (E = h c / λ). The other terms describe individual properties or a single type or instance of radiation, not the entire range. So the spectrum is the whole collection of wavelengths and frequencies used to categorize and study EM radiation as a continuum.