Department of Pre-University Education, KarnatakaPUC Karnataka Science Class 12

# The Constants A And B For the Pair Silver-lead Are 2.50 μV°C−1 And 0.012μV°C−2, Respectively. for a Silver-lead Thermocouple with Colder Junction at 0°C, - Physics

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The constants a and b for the pair silver-lead are 2.50 μV°C−1 and 0.012μV°C−2, respectively. For a silver-lead thermocouple with colder junction at 0°C, ______________ .

(a) there will be no neutral temperature
(b) there will be no inversion temperature
(c) there will not be any thermo-emf even if the junctions are kept at different temperatures
(d) there will be no current in the thermocouple even if the junctions are kept at different temperatures

#### Solution

(a) there will be no neutral temperature
(b) there will be no inversion temperature

The temperature of the hot junction at which the thermo-emf in the thermocouple becomes maximum is called neutral temperature for that thermocouple. The signs of the constants a and are same. Therefore from the relation, $\theta_n = - \frac{a}{b},$ the neutral temperature will be less than the temperature of the cold junction of thermocouple.

Hence, there will be no neutral or inversion temperature, as the temperature of the hot junction cannot be less than the temperature of the cold junction.

Concept: Temperature Dependence of Resistance
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#### APPEARS IN

HC Verma Class 11, Class 12 Concepts of Physics Vol. 2
Chapter 11 Thermal and Chemical Effects of Current
MCQ | Q 3 | Page 218