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31 Cards in this Set
- Front
- Back
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What is the purpose of a cell?
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a cell is a device that converts chemical energy to electrical energy
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What are the three parts of a cell?
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the electrodes, the electrolyte, and the container
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What is the purpose of each of the three parts of a cell?
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the electrodes are the current conductors of the cell. the electrolyte is the solution that acts upon the electrodes. the container holds the electrolyte and provides a means of mounting the electrodes
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What are the two types of cells?
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primary and secondary
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What is the main difference between the two types of cells?
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the secondary cell can be restored to its original condition by an electric current. the primary cell can not
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What is electrochemical action?
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the process of converting chemical energy into electrical energy
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What is another name for the (a) positive electrode, and the (b) negative electrode?
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(a) the anode, (b) the cathode
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In the primary cell, why are negative ions attracted to the negative terminal of the cell?
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the positive charge cause by electrons leaving the negative electrode attracts the negative ions
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How do electrons get from the negative electrode to the positive electrode?
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by current flow through the load
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What causes the negative electrode to be eaten away?
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the chemical action between the negative electrode and the electrolyte
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Describe three ways to prevent polarization.
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vent the ceel, add a material rich in oxygen, and use a material that will abosorb hydrogen.
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Describe local action
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current flow in a cell with no external load
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What serves as the cathode of a dry cell?
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the zinc container
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Why is a dry cell called a DRY cell?
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the electrolyte is not a liquid but is in the form of a paste
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What does the term "shelf life" mean?
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the period that a cell can be stored and still be useable
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Why should a mercury cell NOT be shorted?
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the danger of explosion
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What factors should be considered when selecting a primary cell for a power source?
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cost, size, ease of replacement, and voltage or current needs
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What are the four basic types of secondary (wet) cells?
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lead-acid, nickel-cadmium (NICAD), silver-zinc, and silver-cadmium
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What are the advantages of a nicad cell over a lead-acid cell?
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can be charged in a shorter time, can deliver a larger amount of power, and stays idle longer
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What type of cell is most commonly used for emergency systems?
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silver-zinc cell
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What three cells use the same electrolyte?
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silver-cadmium, silver-zinc, and nickel-cadmium
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What does the term battery normally refer to?
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a voltage source in a single container made from one or more cells
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What are the three ways of combining cells, and what is each used for?
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series, to increase voltage but not current. Parallel, to increase current but not voltage. Series-Parallel, to increase both current and voltage
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Other than the type of cell used, what is the major difference between the construction of the leadacid
and nicad battery? |
the cells in the nicad battery can be replaced
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How is the type of battery most easily determined?
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by looking at the nameplate data
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What is the purpose of the hydrometer?
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to measure the amount of active ingredient in the electrolyte
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Which electrolyte has more active ingredient? Electrolyte A, specific gravity 1.015? Electrolyte B,
specific gravity 1.125? |
electolyte B. it is heavier per unit volume
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When should safety precautions pertaining to batteries be observed?
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at all times
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How long should a 200 ampere-hour battery be able to deliver 5 amperes?
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forty hours
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Can a battery be recharged by adding more electrolyte?
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No, a current must be passed through the battery
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If violent gassing occurs during a battery charge, what action should be taken?
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reduce the charging rate
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