Which statement correctly describes the major sources of radio frequency radiation in occupational settings?

• A. Microwave and communication frequencies are the major sources of RF radiation.
• B. X-ray machines are the major RF sources.
• C. Visible light sources are the major RF sources.
• D. Cosmic radiation is the major RF source.

Answer: (A)

Radio frequency radiation is the part of the electromagnetic spectrum from about 3 kHz up to 300 GHz. In workplaces, the main sources are devices that deliberately emit RF to transmit energy or information, such as microwave systems and radio/communication equipment. That’s why microwave and communication frequencies are the major sources: they encompass the common occupational RF activities like radar, wireless transmitters, and RF heating processes.

X-ray machines, visible light, and cosmic radiation lie outside the RF range. X-rays are ionizing radiation at much higher energies; visible light is optical and not in the RF band; cosmic radiation consists of high-energy particles and photons outside RF. So those sources do not represent major RF exposure in occupational settings.