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Difficulty: MediumDirect Fact Retrieval

Naval vessel battery compartments require dedicated forced-air exhaust ventilation during bulk charging cycles. When submerged lead-acid cells undergo charging exceeding 2.35 volts per cell, electrolysis of the water in the electrolyte solution generates volatile hydrogen gas. To prevent explosive concentrations, exhaust blowers must maintain hydrogen levels strictly below 1.5 percent by volume. If compartment sensors detect hydrogen concentrations reaching 2.0 percent, charging current automatically terminates, and secondary emergency intake fans activate immediately to flush the compartment with fresh atmospheric air.

According to the passage, what automatic action occurs when hydrogen concentration in the battery compartment reaches 2.0 percent?

  1. A
    Cell voltage automatically increases above 2.35 volts.
  2. The charging current is automatically cut off.Answer
  3. C
    Exhaust blowers activate to keep hydrogen levels strictly below 1.5 percent.
  4. D
    Secondary intake fans activate to add water to the electrolyte solution.

Answer

The charging current is automatically cut off.
The passage explicitly states that when hydrogen levels reach 2.0 percent, charging current automatically terminates, which means the charging current is cut off.

Step-by-Step Solution

1
Locate the key condition in the stem within the passage.
Found the reference to 'hydrogen concentrations reaching 2.0 percent' in the final sentence.
Direct fact retrieval requires pinpointing the exact factual condition stated in the question.
2
Extract the explicit result tied directly to this condition.
The text explicitly states that 'charging current automatically terminates' and emergency fans activate.
Direct fact retrieval relies solely on explicit statements without external deduction or inference.

Key Concept

Direct Fact Retrieval
Estimated Time:50s
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Direct Fact Retrieval

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