Is RF safety on the ham radio Technician exam?

Radio signals are non-ionizing radiation: they do not carry enough energy to cause chemical changes in cells or damage DNA, but strong RF energy can heat body tissue. The FCC therefore sets maximum permissible exposure limits, and those limits change with frequency because the body absorbs RF energy more readily at some frequencies than at others.

Exposure near an antenna depends on the transmitter power, the frequency, the distance to the antenna and the antenna's radiation pattern. Duty cycle matters too: a transmitter that is on only half the time produces half the average exposure. The station licensee is responsible for making sure nobody is exposed above the limits, and should evaluate the station again whenever the transmitter or antenna system changes. Touching an antenna while it transmits can cause an RF burn.