THERMOELECTRIC POWER OF A GIVEN THERMOCOUPLE
THERMOELECTRIC POWER OF A GIVEN THERMOCOUPLE
HIGHLIGHTS
- AIM
- APPARATUS
- THEORY
- OBSERVATION TABLE
- GRAPH
- CALCULATION
- CONCLUSION
AIM
Determination of thermoelectric power at a certain temperature of the given thermocouple.
APPARATUS
Thermocouple kit with copper-constantan thermocouple, emersion heater, thermometer, beaker etc.
THEORY
A thermocouple is prepared by soldering two wires of each other. A small voltage in the millivolt range is generated. The induced is temperature-dependent. If the two junctions of that thermocouple are kept at a different temperature, a small current will flow around the wire loop.
Basically, a temperature difference produce a potential difference and the phenomenon is known as thermoelectric effect.
When one junction of thermocouple is kept at room temperature and the other junction at some higher temperature, a thermo emf developed in the thermocouple. Measuring thermo emf at between E & T can be drawn.
OBSERVATION TABLE
Temperature of the cold junction = Room temperature
|
TEMPERATURE OF HOT JUNCTION(°C)
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THERMO EMF (mv)
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95°C
|
2.6mv
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85°C
|
2.2mv
|
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75°C
|
1.8mv
|
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65°C
|
1.4mv
|
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55°C
|
1.0mv
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45°C
|
0.6mv
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GRAPH
A graph is to be drawn between thermo emf (mv) and temperature (°C)
CALCULATION
A(45,0.6)
B(55,1.0)
SLOPE = 1 - 0.6 = 0.04 mv/°C
55-45
CONCLUSION
Therefore the required thermoelectric power of the given thermocouple is 0.04mv/°C.