Which of the following instruments uses the difference in temperature as a measure of the relative humidity?
A
Hydrometer
B
Thermometer
C
Barometer
D
Hygrometer
Verified Correct Answer: D.
Step-by-Step Mathematical Solution
A hygrometer (specifically a wet-and-dry bulb hygrometer/psychrometer) uses the difference in temperature between a wet bulb and a dry bulb to measure relative humidity.
Source: WAEC / JAMB / NECO Classroom Archive (Record #78291)