A constant-volume gas thermometer uses nitrogen gas and a mechanical pressure gauge
PHYSICS · Multi-part · CBSE · Physics · Thermal Properties of Matter · Thermal Properties of Matter
Problem
A constant-volume gas thermometer uses nitrogen gas and a mechanical pressure gauge. After the experiment, technicians discover that every pressure reading recorded during the run was 5.0 % higher than the true pressure because of a systematic calibration error in the gauge spring. The raw (uncorrected) linear fit obtained by the student during the run was
Praw=0.375T+102 (kPa),
where T is in ∘C and Praw is the erroneous pressure.
(a) Using the raw equation, determine the Celsius temperature at which the pressure would be predicted to reach zero.
(b) Derive a corrected equation Ptrue(T) that accounts for the 5.0 % systematic error, and use it to obtain a corrected value of absolute zero in ∘C.
(c) Compare the uncorrected and corrected absolute zero temperatures, explaining quantitatively how the systematic error affects both the slope and intercept of the pressure–temperature relationship.
(d) Propose one experimental modification that could reduce the uncertainty in the determination of absolute zero and justify how it addresses a specific source of error.