Question

The temperature of inversion of a thermocouple is 620°C and the neutral temperature is 300°C.what is the temperature of cold junction?

• A. 20°C
• B. 120°C
• C. -20°C
• D. -120°C

Answer 1

Answer: (C)

-20°C

Answer 2

Similar to how the neutral temperature is greater than the temperature of the cold junction, the temperature of the inversion is higher than the neutral temperature.
In accordance with the key idea, tn - t0 = ti - tn
$\Rightarrow$ t0 =2tn - ti
given, ti = 620$\degree$ C , and tn = 300$\degree$ C.
Consequently, t0 = temperature of the cold junction
= 2 $\times$ 300 - 620 = 600 - 620
= - 20$\degree$ C

Therefore, the correct option is (C): - 20$\degree$ C