Ordinary mercury in glass thermometer is used for measuring temperature upto 120°C. However, for measuring higher temperature upto __________ °C, thermometer is made by filling nitrogen under pressure above the mercury, which stops the evaporation of mercury and reduces the chance of broken thread of mercury?
Correct answer: C. 550
- A. 250
- B. 350
- C. 550
- D. 700
Explanation
Pressurising the space above mercury with nitrogen suppresses mercury vapour formation and prevents separation of the mercury column, extending the thermometer range to about 550°C. The other listed limits are not the standard range for this construction.
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