Topic T0A Quick Review Audio


Which of the following is a safety hazard of a 12-volt storage battery?

  1. Touching both terminals with the hands can cause electrical shock
  2. Shorting the terminals can cause burns, fire, or an explosion
  3. RF emissions from the battery
  4. All of these choices are correct


What health hazard is presented by electrical current flowing through the body?

  1. It may cause injury by heating tissue
  2. It may disrupt the electrical functions of cells
  3. It may cause involuntary muscle contractions
  4. All of these choices are correct


In the United States, what is connected to the green wire in a three-wire electrical AC plug?

  1. Neutral
  2. Hot
  3. Equipment ground
  4. The white wire


What is the purpose of a fuse in an electrical circuit?

  1. To prevent power supply ripple from damaging a circuit
  2. To interrupt power in case of overload
  3. To limit current to prevent shocks
  4. All of these choices are correct


Why is it unwise to install a 20-ampere fuse in the place of a 5-ampere fuse?

  1. The larger fuse would be likely to blow because it is rated for higher current
  2. The power supply ripple would greatly increase
  3. Excessive current could cause a fire
  4. All of these choices are correct


What is a good way to guard against electrical shock at your station?

  1. Use three-wire cords and plugs for all AC powered equipment
  2. Connect all AC powered station equipment to a common safety ground
  3. Use a circuit protected by a ground-fault interrupter
  4. All of these choices are correct


Which of these precautions should be taken when installing devices for lightning protection in a coaxial cable feed line?

  1. Include a parallel bypass switch for each protector so that it can be switched out of the circuit when running high power
  2. Include a series switch in the ground line of each protector to prevent RF overload from inadvertently damaging the protector
  3. Keep the ground wires from each protector separate and connected to station ground
  4. Mount all of the protectors on a metal plate that is in turn connected to an external ground rod


What safety equipment should always be included in home-built equipment that is powered from 120V AC power circuits?

  1. A fuse or circuit breaker in series with the AC hot conductor
  2. An AC voltmeter across the incoming power source
  3. An inductor in parallel with the AC power source
  4. A capacitor in series with the AC power source


What should be done to all external ground rods or earth connections?

  1. Waterproof them with silicone caulk or electrical tape
  2. Keep them as far apart as possible
  3. Bond them together with heavy wire or conductive strap
  4. Tune them for resonance on the lowest frequency of operation


What can happen if a lead-acid storage battery is charged or discharged too quickly?

  1. The battery could overheat, give off flammable gas, or explode
  2. The voltage can become reversed
  3. The memory effect will reduce the capacity of the battery
  4. All of these choices are correct


What kind of hazard might exist in a power supply when it is turned off and disconnected?

  1. Static electricity could damage the grounding system
  2. Circulating currents inside the transformer might cause damage
  3. The fuse might blow if you remove the cover
  4. You might receive an electric shock from the charge stored in large capacitors