Question #2e732

1 Answer
Mar 11, 2017

The building's height #h=200m#.
So the barometer reading at lower floor is higher than the upper floor due to the pressure exerted by 200m air column.

Pressure exerted by the air column
#=h xxd xxg#
Where #d= "density of air and g = acceleration due to gravity"#

The barometer reading difference gives the pressure difference of #76-74.15=1.85cm=1.85 xx10^-2m# of Hg column.

Here the barometric pressure difference is equal to the pressure of 200m air column.

Let the density of air be #d "kg/" m^3#

So

#200xxd xxg=(76 -74.15)xx10^-2xx13600xxg#

#d=(1.85xx10^-2xx13600)/200"kg/"m^3#

#=1.285" kg/"m^3#