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Electric Power

A chromel-alu...

Question

A chromel-alumel Thermocouple is asssumed to have nearly Linear operating range upto $1100^{o} C$ with emf $($ reference junciton temperature $0^{0} C) 45.14 m V$ at this temperature. The Thermocouple is exposed to a temperature of $840^{o} C$ . If the poteniometer is used as the cold junciton and its temperature is estimated to be $25^{o} C$ . Then the emf indicated on the potentiometer is _____ $m V$ .
33.44

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Solution

The correct option is A 33.44
$Sensitivty of Thermocouple = \frac{45.14}{1100}$

$S = 41.03 μ V /^{o} C$

$Output of thermocouple,$

$= S [T_{m} - T_{p o t}] = 41.03 [840 - 25] = 33.44 m V$

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