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Multiple Choice Questions on Cathodic Protection |
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| Questions 11 - 15 |
Page 3 of 4 |
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11. |
A soil resistivity of 1000 ohm-cm indicate |
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a highly corrosive soil |
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moderately corrosive soil |
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less corrosive soil |
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corrosive soil |
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12. |
Which one of the following conditions would require a higher current density for cathodic protection? |
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Water moving with a high velocity |
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Well coated steel in earth |
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Poorly coated steel in earth |
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Bare steel in quite water |
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13. |
If aluminum is to be protected, the potential must be maintained in the following range |
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-0.85 to -0.10 V |
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-1.01 to -1.2 V |
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-1.3 to -1.5 V |
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-1.5 to -1.6 V |
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14. |
The anode backfill for galvanic anodes serves which of the purpose? |
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It increases the resistivity of the anode, thereby reducing the consumption rate |
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It extends the life of the galvanic anode |
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It provides a lower anode-to-earth resistance |
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15. |
Stray current originating from DC transit systems may cause considerable damage to protected structures. To avoid this undesirable damage |
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a high resistivity soil should be placed in the path of the current |
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the pipe on the way must be well coated |
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the stray current must be returned to the positive terminal of a DC substation |
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a conducting wire may be placed between the pipe and the negative terminal of the substation |
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