Assuming the internal emissivity compensation for the radiometer in Prob. 12.18 is exact, what temperature will be indicated when the instrument is set for the nominal value obtained in Prob. 12.18?
Prob. 12.18:
Repeat Prob. 12.11 for an indicated temperature of 200?C when ε is set equal to 1.0.
Prob. 12.11:
The emissivity-parameter procedure described in the paragraphs following Eq. (12.2) is used to determine the emissivity of a surface at 300?C. The surrounding radiation temperature is only 25?C and thus is expected to have little influence on the measurement. With = 1.0, the apparent temperature is indicated as 231?C. The uncertainty in the radiometer indication of temperature is ±3?C and the uncertainty in the surface-temperature measurement is ±1?C. What surface emissivity is indicated by these measurements? What is its uncertainty?
