The instrument used to mark the upper fixed point of an unmarked thermometer is the
A
calibrator
B
hydrometer
C
hypsometer
D
constant volume gas thermometer
Verified Correct Answer: C.
Physical Principles & Numerical Solution
A hypsometer is used to determine the boiling point of water (upper fixed point) for calibrating thermometers.
Source: Myschool Past Questions Archive (Record #78261)