In a particular industrial situation, a nicrosil-nisil thermocouple with nicrosil-nisil extension wires is used to measure the temperature of a fluid. In connecting up this measurement system, the instrumentation engineer responsible has inadvertently interchanged the extension wires from the thermocouple. The ends of the extension wines are held at a reference temperature of 0° C and the output e.m.f. measured is 21.0mV. If the junction between the thermocouple and extension wires is at a temperature of 50° C, what temperature of fluid is indicated and what is the true fluid temperature?