Question

For a thermocouple, if $a=4.5\times {10}^{-5}V{/}^{0}C$, $b=-2\times {10}^{-7}V{/}^0{C}^2$ , thermoelectric power at ${1000}^0$C is $(E=at+b{t}^2)$

• A. $25\mu V{/}^{0}C$
• B. zero
• C. $5\mu V{/}^{0}C$
• D. $45\mu V{/}^{0}C$

Answer 1

The correct option is C $5\mu V{/}^{0}C$

The temperature here should be ${100}^{o}C$

Thermoelectric power is $P=dE/dt=a+2bt$.

So at $t={100}^{o}C$,

$P=4.5\times {10}^{-5}+2\times (-2\times {10}^{-7})\times 100$

$\Rightarrow P=45\times {10}^{-6}-40\times {10}^{-6}=5\mu V/{}^{o}C$