Ultraviolet radiation is the highest energy non-ionizing radiation.

• A. Ultraviolet radiation is the highest energy non-ionizing radiation.
• B. Ultraviolet radiation is ionizing.
• C. Infrared radiation has higher energy than ultraviolet.
• D. Radiofrequency radiation is non-ionizing but has highest energy.

Answer: (A)

Photons carry more energy as their frequency increases, and non-ionizing radiation consists of photons that are not energetic enough to knock electrons off atoms. Ultraviolet sits at the high-energy end of the non-ionizing range, with photon energies greater than those of infrared, visible, microwave, and radio waves, but still below the energies of X-rays and gamma rays, which are ionizing. That makes ultraviolet the highest energy form within the non-ionizing category. The other statements don’t fit because infrared, radiofrequency, and even the idea of ultraviolet being ionizing are inaccurate within this classification.