Using the psychrometric chart, find the specific humidity if the dry-bulb temperature is 20 degrees C and the wet-bulb temperature is 15 degrees C.
a) 0.009 kg of water vapour per kg of dry air
b) 0.008 kg of water vapour per kg of dry air
c) 0.010 kg of water vapour per kg of dry air
d) 0.0085 kg of water vapour per kg of dry air
e) 0.0085 kg of dry air per kg of water vapour
Answer: D