Microwave and communication frequencies are the major sources of radio frequency radiation.

• A. True
• B. False
• C. Microwave and communication frequencies are the major sources of radio frequency radiation
• D. Only in some industries

Answer: (C)

The main idea here is that in most workplaces, the bulk of radio frequency energy people are exposed to comes from devices that operate in the microwave and communications bands. The microwave range (roughly 1 GHz and above) includes high‑power equipment such as microwave ovens, radar, and some industrial heating devices. The communications bands cover the methods we rely on to transmit information—cellular networks, Wi‑Fi, Bluetooth, radio and television broadcasting, two‑way radios, and related wireless systems. These technologies are widespread and often emit RF energy continuously or for long periods, so they contribute the most to occupational RF exposure.

Other RF sources exist, but they’re typically less common in everyday workplaces or don’t emit at the same power levels as the common wireless and microwave equipment, so they don’t dominate exposure in the general occupational setting. That’s why saying these frequencies are the major sources aligns with how RF exposure is viewed in practice.