Answer:
The water level will drop by about 1.24 cm in 1 day.
Explanation:
Here Mass flux of water vapour is given as

where
is the mass flux of the water which is to be calculated.
- D is diffusion coefficient which is given as

- l is the thickness of the film which is 0.15 cm thick.
is given as

In this
is the saturated water pressure, which is look up from the saturated water property at 20°C and 0.5 saturation given as 2.34 Pa
is the air pressure which is given as 0.5 times of 
- R is the universal gas constant as

- T is the temperature in Kelvin scale which is

By substituting values in the equation

Converting
into 
As 1 mole of water 18
so

Putting this in the equation of mass flux equation gives

For calculation of water level drop in a day, converting mass flux as

So the water level will drop by about 1.24 cm in 1 day.
Answer:
d = 380 feet
Explanation:
Height of man = perpendicular= 130 feet
Angle of depression = ∅ = 70 °
distance to bus stop from man = hypotenuse = d = 130 sec∅
As sec ∅ = 1 / cos∅
so d = 130 sec∅ or d = 130 / cos∅
d = 130 / cos(70°)
d = 380 feet
Since we are given the density and volume, then perhaps we can determine the amount in terms of the mass. All we have to do is find the volume in terms of cm³ so that it will cancel out with the cm³ in the density. The conversion is 1 ft = 30.48 cm. The solution is as follows:
V = (14 ft)(15 ft)(8 ft)(30.48 cm/1 ft)³ = 0.0593 cm³
The mass is equal to:
Mass = (0.00118g/cm³)(0.0593 cm³)
Mass = 7 grams of HCN