Calculate the work done in breaking up a drop of petrol of

Question

Problem 1

Calculate the work done in breaking up a drop of petrol of volume 1 cm³ into 10⁹ drops. Surface tension of petrol is given as 26 dynes/cm.

Problem 2

Find the pressure difference inside and outside a rain drop of diameter 0.02 cm. What would be this pressure if on evaporation, drop reduces to a size of 2x10^-5cm .

Problem 3

Water rises to a height of 5 cm in a certain glass capillary tube. In the same tube the level of mercury surface is depressed by 1.54cm. Compare the surface tensions of water and mercury. Specific weight of Mercury is 13.6 x10³ Kg/m³ and that of water is

10³ Kg/m³. Angle of contact of glass with mercury and water is 130^° and 0^°, respectively.

Problem 4

Experimental values of surface tensions of a few metals and other substances are shown below.

Material                    y, J/m²        T,°C

W (solid)                   2.900          1727

Au(solid)                   1.410          1027

Estimation of three dimensional pressure, P, for the solid surface (W and Au, respectively).

Assuming the thickness of the interaction is a few atomic layers (-1 nm)