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Amateur Radio Question PoolsNew! View the differences between the 2008 Extra question pool and the previous pool. Amateur Extra (Eff. July 2008) Question PoolPrev 1 2 3 4 5 6 7 8 9 0 NextE0A01 What, if any, are the differences between the radiation produced by radioactive materials and the electromagnetic energy radiated by an antenna? There is no significant difference between the two types of radiation Only radiation produced by radioactivity can injure human beings RF radiation does not have sufficient energy to break apart atoms and molecules; radiation from radioactive sources does Radiation from an antenna will damage unexposed photographic film, ordinary radioactive materials do not cause this problem E0A02 When evaluating exposure levels from your station at a neighbor’s home, what must you do? Make sure signals from your station are less than the controlled MPE limits Make sure signals from your station are less than the uncontrolled MPE limits Nothing; you need only evaluate exposure levels on your own property Advise your neighbors of the results of your tests E0A03 Which of the following would be a practical way to estimate whether the RF fields produced by an amateur radio station are within permissible MPE limits? Use a calibrated antenna analyzer Use a hand calculator plus Smith-chart equations to calculate the fields Walk around under the antennas with a neon-lamp probe to find the strongest fields Use a computer-based antenna modeling program to calculate field strength at accessible locations E0A04 When evaluating a site with multiple transmitters operating at the same time, the operators and licensees of which transmitters are responsible for mitigating over-exposure situations? Only the most powerful transmitter Only commercial transmitters Each transmitter that produces 5% or more of its maximum permissible exposure limit at accessible locations Each transmitter operating with a duty-cycle greater than 50% E0A05 What is one of the potential hazards of using microwaves in the amateur radio bands? Microwaves are ionizing radiation The high gain antennas commonly used can result in high exposure levels Microwaves often travel long distances by ionospheric reflection The extremely high frequency energy can damage the joints of antenna structures E0A06 Why are there separate electric (E) and magnetic (H) field MPE limits? The body reacts to electromagnetic radiation from both the E and H fields Ground reflections and scattering make the field impedance vary with location E field and H field radiation intensity peaks can occur at different locations All of these answers are correct E0A07 What is the "far-field" zone of an antenna? The area of the ionosphere where radiated power is not refracted The area where radiated power dissipates over a specified time period The area where radiated field strengths are obstructed by objects of reflection The area where the shape of the antenna pattern is independent of distance E0A08 What does SAR measure? Synthetic Aperture Ratio of the human body Signal Amplification Rating The rate at which RF energy is absorbed by the body The rate of RF energy reflected from stationary terrain E0A09 Which insulating material commonly used as a thermal conductor for some types of electronic devices is extremely toxic if broken or crushed and the particles are accidentally inhaled? Mica Zinc oxide Beryllium Oxide Uranium Hexaflouride E0A10 What material found in some electronic components such as high-voltage capacitors and transformers is considered toxic? Polychlorinated biphenyls Polyethylene Polytetrafluroethylene Polymorphic silicon E0A11 Which of these items might be a significant hazard when operating a klystron or cavity magnetron transmitter? Hearing loss caused by high voltage corona discharge Blood clotting from the intense magnetic field Injury from radiation leaks that exceed the MPE limits Ingestion of ozone gas from the cooling system |
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