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Raptor112
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Homework Statement
On a winter day, suppose your breath has a temperature of 30°C and a dew point of 28°C,and it mixes with the ambient air of temperature –10°C and a dew point of –11°C. Will you see your breath? Assume you are at sea level, and that your breath and the environment mix in proportions of 2 parts (by mass) breath to 1 part (by mass)
environment. Show all your working.
Homework Equations
##\frac{p_1}{p_2} = e ^{\frac{L}{R_s}(\frac{1}{t_2}- \frac{1}{t_1})}##
## Relative Humidity = \frac{actual vapour pressure}{saturated vapour pressure} *100##
The Attempt at a Solution
Found the relative humidity of the breath and air by using, for air:
##t_1 = -10, t_2 = -11##
and for breath
##t_1 = 30, t_2 = 28##
which gives
Relative humidity of air =114%
Relative humidity of breath= 108%
using ##L =2.5 *10^6 Jkg^-1##
##R_s = 461 J K^-1 kg^-1##