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)	THERMO EMF (mv)
95°C	2.6mv
85°C	2.2mv
75°C	1.8mv
65°C	1.4mv
55°C	1.0mv
45°C	0.6mv

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.