Questions - Safety

Question file 10


  1. You can safely remove an unconscious person from contact with a high voltage source by:
    1. pulling an arm or a leg
    2. wrapping the person in a blanket and pulling to a safe area            STUDY NOTES 
    3. calling an electrician
    4. turning off the high voltage and then removing the person   QUESTIONS WITHOUT ANSWERS 
    ========= Answer is d =========
  2. For your safety, before checking a fault in a mains operated power supply unit, first:
    1. short the leads of the filter capacitor
    2. turn off the power and remove the power plug
    3. check the action of the capacitor bleeder resistance
    4. remove and check the fuse in the power supply
    ========= Answer is b =========
  3. Wires carrying high voltages in a transmitter should be well insulated to avoid:
    1. short circuits
    2. overheating
    3. over modulation
    4. SWR effects
    ========= Answer is a =========
  4. A residual current device is recommended for protection in a mains power circuit because it:
    1. reduces electrical interference from the circuit
    2. removes power to the circuit when the phase and neutral currents are not equal
    3. removes power to the circuit when the current in the phase wire equals the current in the earth wire
    4. limits the power provided to the circuit
    ========= Answer is b =========
  5. An earth wire should be connected to the metal chassis of a mains-operated power supply to ensure that if a fault develops, the chassis:
    1. does not develop a high voltage with respect to earth
    2. does not develop a high voltage with respect to the phase lead
    3. becomes a conductor to bleed away static charge
    4. provides a path to ground in case of lightning strikes
    ========= Answer is a =========
  6. The purpose of using three wires in the mains power cord and plug on amateur radio equipment is to:
    1. make it inconvenient to use
    2. prevent the chassis from becoming live in case of an internal short to the chassis
    3. prevent the plug from being reversed in the wall outlet
    4. prevent short circuits
    ========= Answer is b =========
  7. The correct colour coding for the phase wire in a flexible mains lead is:
    1. brown
    2. blue
    3. yellow and green
    4. white
    ========= Answer is a =========
  8. The correct colour coding for the neutral wire in a flexible mains lead is:
    1. brown
    2. blue
    3. yellow and green
    4. white
    ========= Answer is b =========
  9. The correct colour coding for the earth wire in a flexible mains lead is:
    1. brown
    2. blue
    3. yellow and green
    4. white
    ========= Answer is c =========
  10. An isolating transformer is used to:
    1. ensure that faulty equipment connected to it will blow a fuse in the distribution board
    2. ensure that no voltage is developed between either output lead and ground
    3. ensure that no voltage is developed between the output leads
    4. step down the mains voltage to a safe value
    ========= Answer is b =========