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# NAVEDTRA 14173A CH3

### Matter, Energy, and Direct Current MAR 2017 ET2 BIBS

Question | Answer |
---|---|

What is any device called in which an electrical current flows and which changes this electrical energy into a more useful form? | Load |

Which device furnishes (supplies) the electrical energy used by the load? | Source |

What permits control of the electrical device and interrupts the current delivered to the load? | switch |

What is the technician's main aid in troubleshooting a circuit in a piece of equipment? | schematic diagram |

What is current inversely proportional to? | Resistance |

What is a basic tool used to solve electrical problems? | algebra |

What can be easily constructed to analyze a circuit? | graph |

What is the rate at which work is being done referred to as? | Power |

What unit is electrical power measured in? | Watts |

What is the basic unit of power? | watt |

What indicates the rate at which devices convert electrical energy into another form of energy? | Power rating |

In most circuits, the actual power used by a resistor is considerably less than the power rating of the resistor because a safety factor of what percent is used? | 50% |

When resistors with wattage ratings greater than how many watts are needed, wirewound resistors are used? | greater than 5 watts |

Wirewound resistors are made in values between 5 and how many watts? | 200 |

Which electrical device property is the ratio of power converted to useful energy divided by the power consumed by the device? | Efficiency |

How many watts are required to equal one horsepower? | 746 W |

What is a complete conducting pathway called? | electrical circuit |

Which type of circuit contains only one path for current flow? | series |

Each of the resistors in a series circuit consumes power which is dissipated in the form of what? | Heat |

The total resistance of a series circuit is equal to the sum of the what? | Individual resistances |

Which law states that "The algebraic sum of the voltage drops in any closed path in a circuit and the electromotive forces in that path is equal to zero."? | Kirchhoff's voltage law |

What are emf sources that would tend to force current in opposite directions said to be? | series opposing |

What is an arbitrarily chosen point to which all other points in the circuit are compared? | reference point |

Which term is used to denote a common electrical point of zero potential? | Ground |

What is a common ground for the many electrical circuits in most electrical equipment? | metal chassis |

What is a circuit said to be when a break exists in a complete conducting pathway/ | open |

What is an accidental path of low resistance which passes an abnormally high amount of current called? | short circuit |

All sources of electromotive force have some form of internal resistance which causes a drop in what as current flows through the source? | Terminal voltage |

What is the total resistance of resistors in parallel also referred to as? | Equivalent resistance |

The equivalent resistance of a parallel circuit is always less than the resistance of any what? | Branch |

Any complex circuit consisting of resistances can be redrawn (reduced) to a basic equivalent circuit containing the voltage .source and a single resistor representing total resistance. This process is called reduction to a what? | Equivalent circuit |

Which type of circuits consist of both series and parallel elements? | combination |

What are the points where the current divides called? | junction |

What are installed in equipment circuits to prevent damage cause by increases in current? | fuses |

Approximately what percent of the load current should the current in a voltage divider resistor equal? | 10% |

Which type of current does not flow through any of the load devices? | bleeder |

The resistance of the human body cannot be relied upon to prevent a fatal shock from how many volts or less? | 115V |

Fatalities from voltages as low as how many volts have been recorded? | 30V |

Tests have shown that body resistance under favorable conditions may be as low as 300 ohms, and possibly as low as how many ohms from temple to temple if the skin is broken? | 100 ohms |

What is used to fight electrical fires because it is nonconductive and the safest to use in terms of electrical safety? | Carbon dioxide (CO2) |

What is the process by which a person who has stopped breathing can be saved called? | artificial ventilation |

Victims of electric shock can be revived when artificial respiration is started in less than how many minutes? | 3 min |

Which technique has been developed to provide aid to a person who has stopped breathing and suffered a cardiac arrest? | Cardiopulmonary Resuscitation (CPR) |