In a clinical thermometer the mercury in the capillary tube does not contract once removed from the patient because_______________?
Correct answer: C. The capillary tube has a small constriction near the bulb
- A. Mercury takes a long time to contract
- B. The amount of mercury use is very small
- C. The capillary tube has a small constriction near the bulb
- D. The capillary tube is very narrow
Explanation
A clinical thermometer has a narrow constriction near the bulb that prevents the mercury column from returning immediately when the thermometer is removed. The reading can therefore be observed after removal. The likely wrong choice is d, because the narrow capillary makes small temperature changes visible but does not itself lock the mercury column.
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