This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Environment and Health, Subject name: Social & Preventive Medicine
Sling Psychrometer is used to measure- 
Select and explain. 
A. Cooling power, B. Air velocity, C. Wind direction, D. Humidity
D: Humidity
Answer: D: Humidity 
Explanation: Ans. is 'd' i.e., Humidity Instruments MeasureSling psychrometer} Assmann psychrometerHumidityDry & wet bulb hygrometer Kata thermameter-Cooling power and air velocityGlobe thermameter-Radiant tempratureAnemometer-Air velocityWind vane-Wind (air) directionSound level meter-Intensity of soundBond frequency analyzer-Characteristic (pitch) of sound