Final answer:
The e.m.f generated by a P type thermocouple can be calculated using the Seebeck coefficients of the materials used in the thermocouple. At 300 degrees Celsius, with a pure platinum positive leg and a platinum-rhodium alloy negative leg, the e.m.f is -4 microvolts.
Step-by-step explanation:
A P type thermocouple is used to measure temperatures. To calculate the e.m.f generated, we first need to know the thermoelectric properties of the materials used in the thermocouple.
Assuming the P type thermocouple is made of pure platinum as the positive leg and a platinum-rhodium alloy (90% platinum and 10% rhodium) as the negative leg, we can use the Seebeck coefficients for these materials to calculate the e.m.f.
At 300 degrees Celsius, the Seebeck coefficient for pure platinum is 0 microvolts/degree Celsius, and for the platinum-rhodium alloy, it is -4 microvolts/degree Celsius. The e.m.f can be calculated by subtracting the Seebeck coefficient of the positive leg from the negative leg: -4 - 0 = -4 microvolts.