Question

When cold junction is at $0^{0}C$, variation of thermo emf (e) of Fe-Cu thermo couple with temperature of hot junction 't' is given as $e=14t-0.02t^2$. It's neutral temperature is

• A. ${175}^{0}C$
• B. ${1400}^{0}C$
• C. ${700}^{0}C$
• D. ${350}^{0}C$

Answer 1

The correct option is D ${350}^{0}C$

Given: emf, $e=14t-0.02t^2$

For the neutral temperature, $t=t_n$, $\frac{dE}{dt}=0$

So, $14-0.02\left(2t_n\right)=0$

$\Rightarrow t_n={350}^{o}C$