FCC Technician Class Exam Study Guide - 2014-2018/Subelement T0 Group C

Question Introduction T0C - RF hazards: radiation exposure; proximity to antennas; recognized safe power levels; exposure to others; radiation types; duty cycle The Question Pool Question 1 What type of radiation are VHF and UHF radio signals? A. Gamma radiation B. Ionizing radiation C. Alpha radiation D. Non-ionizing radiation The correct answer is D. Question 2 Which of the following frequencies has the lowest value for Maximum Permissible Exposure limit? A. 3.5 MHz B. 50 MHz C. 440 MHz D. 1296 MHz The correct answer is B. Question 3 What is the maximum power level that an amateur radio station may use at VHF frequencies before an RF exposure evaluation is required? A. 1500 watts PEP transmitter output B. 1 watt forward power C. 50 watts PEP at the antenna D. 50 watts PEP reflected power The correct answer is C. Question 4 What factors affect the RF exposure of people near an amateur station antenna? A. Frequency and power level of the RF field B. Distance from the antenna to a person C. Radiation pattern of the antenna D. All of these choices are correct The correct answer is D. Question 5 Why do exposure limits vary with frequency? A. Lower frequency RF fields have more energy than higher frequency fields B. Lower frequency RF fields do not penetrate the human body C. Higher frequency RF fields are transient in nature D. The human body absorbs more RF energy at some frequencies than at others The correct answer is D. Question 6 Which of the following is an acceptable method to determine that your station complies with FCC RF exposure regulations? A. By calculation based on FCC OET Bulletin 65 B. By calculation based on computer modeling C. By measurement of field strength using calibrated equipment D. All of these choices are correct The correct answer is D. Question 7 What could happen if a person accidentally touched your antenna while you were transmitting? A. Touching the antenna could cause television interference B. They might receive a painful RF burn C. They might develop radiation poisoning D. All of these choices are correct The correct answer is B. Question 8 Which of the following actions might amateur operators take to prevent exposure to RF radiation in excess of FCC-supplied limits? A. Relocate antennas B. Relocate the transmitter C. Increase the duty cycle D. All of these choices are correct The correct answer is A. Question 9 How can you make sure your station stays in compliance with RF safety regulations? A. By informing the FCC of any changes made in your station B. By re-evaluating the station whenever an item of equipment is changed C. By making sure your antennas have low SWR D. All of these choices are correct The correct answer is B. Question 10 Why is duty cycle one of the factors used to determine safe RF radiation exposure levels? A. It affects the average exposure of people to radiation B. It affects the peak exposure of people to radiation C. It takes into account the antenna feed line loss D. It takes into account the thermal effects of the final amplifier The correct answer is A. Question 11 What is the definition of duty cycle during the averaging time for RF exposure? A. The difference between the lowest power output and the highest power output of a transmitter B. The difference between the PEP and average power output of a transmitter C. The percentage of time that a transmitter is transmitting D. The percentage of time that a transmitter is not transmitting The correct answer is C. Question 12 How does RF radiation differ from ionizing radiation (radioactivity)? A. RF radiation does not have sufficient energy to cause genetic damage B. RF radiation can only be detected with an RF dosimeter C. RF radiation is limited in range to a few feet D. RF radiation is perfectly safe The correct answer is A. Question 13 If the averaging time for exposure is 6 minutes, how much power density is permitted if the signal is present for 3 minutes and absent for 3 minutes rather than being present for the entire 6 minutes? A. 3 times as much B. 1/2 as much C. 2 times as much D. There is no adjustment allowed for shorter exposure times The correct answer is C.