What is the typical rhodium percentage within the platinum-rhodium elements of a thermocouple?
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Answer: C. 13
Explanation
Noble metal thermocouples require specific alloy compositions to maintain accuracy at high temperatures. Type S thermocouples utilize a positive leg composed of platinum combined with 13% rhodium. This precise percentage ensures stable thermoelectric voltage generation across demanding industrial environments. Thermocouples generate a measurable voltage based on the Seebeck effect between dissimilar metals. Platinum-rhodium alloys resist oxidation and corrosion at extremely high operating temperatures reliably. Standard reference tables correlate the resulting millivolt output directly to precise temperature values.
Metallurgical furnaces and high-temperature reactors utilize Type S thermocouples for continuous monitoring. Accurate high-temperature measurement prevents equipment overheating and ensures product quality in manufacturing. Calibration standards rely on these noble metal combinations for precise laboratory temperature measurements. Option A represents an impossibly low percentage of rhodium for standard noble metal thermocouples. Option B specifies a much lower rhodium content typically found in different thermocouple classifications. Option D suggests a rhodium concentration far exceeding standard commercial platinum-rhodium thermocouple designs.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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