Nails that must be driven into very hard substances are ____________________ treated to make them

hard.



Fill in the blank(s) with the appropriate word(s).


ANS: heat

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Answer the following statement(s) true (T) or false (F)

1. Coal-burning power plants are the predominant source of electricity generation in the U.S. 2. The total asset value of electrical facilities in the U.S. is around $8 billion and the industry’s annual sales are around $3 billion, according to the U.S. Department of Energy. 3. An efficient and safe method of meeting peak demands needs is to transport power into the high demand area from another part of the grid where demand is lower. 4. The generating capacity of the smart grid is decentralized. 5. A smart meter is the only device required to make a smart grid home more energy efficient.

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Answer the following statement(s) true (T) or false (F)

1.Service conductors are considered outside of a house when they are installed under at least 2 inches (50 mm) of concrete beneath a house; where installed in a conduit under at least 18 inches (450 mm) of earth beneath a house; or where they are installed in rigid metal conduit (RMC) or intermediate metal conduit (IMC) when used as a service mast that extends through an eave. 2.A coupling connecting two conduits together for a service mast can be located above the last point of securement to the house. 3.Grounding electrode conductors in contact with the earth do not need to comply with the Section 300.5 rules for burial depths when being installed underground but need to be buried or otherwise protected if they are subject to physical damage. 4.If a concrete-encased electrode is used, the end of the 4 AWG copper conductor or the end of the re-bar (whichever is used) can be extended from its location in the concrete to an accessible location above the concrete. 5.A supplemental grounding electrode is a grounding electrode used to “back-up” a metal water pipe grounding electrode.

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What is the purpose of the gas burner venturi?

A) The venturi ensures that the proper amount of gas flows into the burner. B) The venturi mixes the gas and primary air by making them swirl as they pass through. C) The venturi ensures that only gas enters inside the burner while air is directed into the combustion area. D) The venturi makes the flames swirl inside the combustion chamber to increase contact with the heat exchanger and boost efficiency.

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Generally, limit switches are used as ____________________ devices to control the coil of relays and motor starters in control circuits.

Fill in the blank(s) with the appropriate word(s).

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