The temperature of inversion of a thermocouple is $620^{\circ} \mathrm{C}$ and the neutral temperature is…

The temperature of inversion of a thermocouple is $620^{\circ} \mathrm{C}$ and the neutral temperature is $300^{\circ} \mathrm{C}$. What is the temperature of cold junction?
  1. $320^{\circ}$
  2. $20^{\circ} \mathrm{C}$
  3. $-20^{\circ} \mathrm{C}$
  4. $40^{\circ} \mathrm{C}$

Solution

$T_1=620 \mathrm{C}, T_n=300^{\circ} \mathrm{C}$
$\begin{array}{l}
T_n=\frac{T_1+T_C}{2} \\
\text {or } 600 =620+T_C \\
\Rightarrow T_C =-20^{\circ} \mathrm{C}
\end{array}$ ^

Asked in: NEET 2005

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