Difficulty: Easy
Correct Answer: > 800 °C
Explanation:
Introduction / Context:Gas thermometers are primary temperature standards because the equation of state of gases is well understood. Constant-volume types infer temperature from pressure changes at fixed volume. Helium is particularly useful due to chemical inertness and stability at high temperatures, making it suitable for elevated-temperature calibration work.Given Data / Assumptions:
Concept / Approach:With appropriate containment and materials, a helium CVGT can operate well above the ranges of liquid-in-glass or mercury thermometers, reaching very high temperatures for standards and calibration. While gas thermometers can also measure sub-zero temperatures, the question emphasizes suitability for “a temperature of … °C” and expects recognition of helium’s usability at very high temperatures, far beyond typical resistance thermometers’ upper limits.Step-by-Step Solution:
Recall that helium is inert and remains gaseous at extreme temperatures at ambient pressures.Recognize that gas thermometers are used as standards into the high-temperature regime with proper construction.Select the range “> 800 °C” to reflect this capability.Verification / Alternative check:Reference practices in metrology employ noble-gas constant-volume thermometers for high-temperature points where other standard sensors face material limitations.
Why Other Options Are Wrong:
< 100 °C or < 0 °C: far below the distinctive advantage of helium CVGT.> 0 °C: true but trivial; does not capture the intended high-temperature suitability.Common Pitfalls:Confusing general gas thermometry (broad range) with the question’s intent to highlight helium’s high-temperature capability.
Final Answer:> 800 °C
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