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Multiple Choice Questions on Cathodic Protection |
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| Questions 1 - 5 |
Page 1 of 4 |
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1. |
In a corrosion cell on the surface of a pipeline, the current flows from |
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anode to cathode through the electrolyte and from cathode to anode through the metallic path |
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from anode to cathode through the electrolyte and from the anode to cathode in the metallic path |
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from the anode to cathode in the metallic path and cathode to anode in the electrolyte |
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from cathode to anode in metallic path and anode to cathode in the electrolyte |
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2. |
Cathodic protection is caused by electrochemical polarization in the negative cathodic direction. If the pipe is very well insulated |
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more current density would be needed for polarization |
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lesser current density would be needed for polarization |
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insulation has no effect on polarization |
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3. |
In cathodic protection |
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corrosion is completely eliminated |
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corrosion is partially eliminated |
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corrosion is transferred from the protected structure to the external current source |
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corrosion is controlled, monitored, and eliminated |
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4. |
For pipelines buried in soils not having anaerobic bacteria, the entire structure should exhibit a potential of -0.85 volts vs Cu-CuSO4 electrode, if it is to be cathodically protected, because |
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there would be no flow of current between the anodic and cathodic areas |
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at -0.85 volts vs Cu-CuSO4, the potential of the anode shifts to the potential of the cathode and the pipe would be protected |
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at -0.85 volts, the complete structure acquires the potential of the anode and it is protected |
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the pipe-to-soil potential is an established criteria which indicates that the pipe is fully protected under all soil conditions |
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5. |
In the measurement of pipe-to-soil potential of a fully coated pipe |
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the negative terminal of a voltmeter is connected with the pipe through a test station and the positive is connected to a reference electrode and placed on the soil above the pipe |
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the negative terminal of voltmeter is connected to the pipe through a test station and the positive to a reference electrode placed on a location remote to the pipe |
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