<prompt> Psychrometer is used to measure:HumidityAir velocityAir temperatureRadiant heat  <response>: AIR HUMIDITY Air humidity is moisture content of air Air humidity can be measured by: Dry and wet bulb thermometer Hygrometer- most widely used. Sling whirling psychrometer Assman psychrometer Assman psychrometer Air temperature: Sixs maximum-minimum thermometer measures maximum minimum air temperatures reached over a period of time. 