Which electromagnetic wave carries the most energy?

Which electromagnetic wave carries the most energy?

• A. Gamma ray
• B. X-ray
• C. Ultraviolet
• D. Radio wave

Answer: (A)

Energy of electromagnetic waves scales with frequency: higher frequency means higher energy per photon. This comes from E = hf, where h is Planck’s constant and f is frequency. Gamma rays have the highest frequency (and the shortest wavelength) among the options, so each photon carries more energy than a photon of X-ray, ultraviolet, or radio wave. Therefore gamma rays carry the most energy. The other types have lower frequencies, so their photons have less energy per photon, even though the beam’s total energy can vary with intensity.

Energy of electromagnetic waves scales with frequency: higher frequency means higher energy per photon. This comes from E = hf, where h is Planck’s constant and f is frequency. Gamma rays have the highest frequency (and the shortest wavelength) among the options, so each photon carries more energy than a photon of X-ray, ultraviolet, or radio wave. Therefore gamma rays carry the most energy. The other types have lower frequencies, so their photons have less energy per photon, even though the beam’s total energy can vary with intensity.