Difficulty: Easy
Correct Answer: °R = °F + 273
Explanation:
Introduction / Context:
Accurate temperature conversions are essential across thermodynamics, heat transfer, and instrumentation. Rømer, Rankine, Celsius, Fahrenheit, and Kelvin scales often appear in legacy data or vendor specifications; choosing the correct formula avoids significant calculation errors.
Given Data / Assumptions:
Concept / Approach:
Check each formula against the standard relations. Remember that offsets differ between pairs: Rankine and Fahrenheit share degree size but different zero; Kelvin and Celsius share offset at zero. Differences (not absolute values) convert without offsets, but magnitudes scale by 9/5 between °F and °C/K.
Step-by-Step Evaluation:
Verification / Alternative check:
Test with °C = 0: (d) gives °F = 1.8 × 17.778 ≈ 32, as expected. For (a), if °F = 0, formula would give °R = 273, but the actual Rankine at 0 °F is 459.67 °R.
Why Other Options Are Wrong or Right:
Common Pitfalls:
Confusing absolute temperatures with temperature differences; mixing the Kelvin and Rankine offsets; rounding offsets too aggressively.
Final Answer:
°R = °F + 273
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