The diameters of a buble at the surface of a lake is 4 mm and at the bottom of the lake is 1 mm. If atmospheric pressure is 1 atm, what is the depth of the lake ? The density of lake-water and Hg are 1.0 gm/ml and 13.6 gm/ml, respectively. Assume that temperature of lake water is equal to that of atmosphere.Also neglect the contribution of pressure due to surface tension.

What is Aqueous tension ?

When a gas is collected over water, it becomes moist due to water vapour which exerts its own partial pressure at the same temperature of the gas. This partial perssure of water vapours is called aqueous tension. Thus,

A balloon of diameter 20 m weighs 100 kg. Calculate its paylod if it is filled with helium at 1.0 atm and 27 ∘ C. Density of air is 1.2 kg m −3 .(R=0.082 dm 3 atm K −1 mol −1 ).

Calculate payload of a balloon having volume 100 litre. It is filled with helium gas at 0.2486 atm pressureand 300K. Density of air is 1.3 gm/litre and mass of material of balloon is 20 gm.

What is payload of Balloon ?

Payload of a Balloon if defined as maximum mass which a Balloon can carry with in it upward direction.

If:

"V" is the volume of Balloon 

d_out : is the density of out side air

d_in: is the density of gas inside of Balloon.

m:  is Maas of Balloon is m then

Payload= [d_out×V]- [d-in×(V+m)]

Illustrative Example :

(2) A balloon of diameter 20 m weighs 100 kg. Calculate its paylod if it is filled with helium at 1.0 atm and 27 ∘ C. Density of air is 1.2 kg m −3 .(R=0.082 dm 3 atm K −1 mol −1 ).