Question

A thermopile is consisting of three identical thermocouples. The emf temperature relationship of a single thermocouple is given by $V_0=50T\mu V,$ where T is the temperature of heated source in ${(}^{0}C).$ If the output voltage measured across the thermopile is found to be 150mV then the approximate value of $Tin{}^{0}C$ is ?

• A. ${100}^{o}C$
• B. ${50}^{o}C$
• C. $1^{o}C$
• D. ${1000}^{o}C$

Answer 1

The correct option is D ${1000}^{o}C$

$\text{Voltage output of thermopile = 150mV}$

$\therefore \text{Voltage output of one thermocouple =}\frac{150}{3}\text{= 50mV}$

$\therefore \text{Emf - temperature relationship}\Rightarrow V_o=50T\mu V$

$\therefore 50mV=50T\mu V$

$\Rightarrow T=\frac{50mV}{50\mu V}$

$\therefore T={1000}^{0}C$

Note: Since the connection of thermocouple is not mentioned by default it is chosen as series.