A capillary tube of 0.4 mm diameter is placed vertically inside a liquid of density 800 kgm^-3, surface tension 5 x 10^-2Nm^-1 and angle of contact 30°. Calculate the height to which liquid rises in the capillary tube.

Ans: 0.055 m

 A rectangular plate of dimensions 6cm by 4 cm and a thickness of 2 mm is placed. with its largest face flat on the surface of water. Calculate the downward force on the plate due to surface tension assuming zero angle of contact. What is the downward force if the plate is placed vertical so that it's longest side just touches the water?

Ans: 1.4 x 10^-2 N, 8.92 x 10^-3 N

Find the work done required to break up a drop of water of radius 5 x 10^-3 m into eight drops of Water, assuming isothermal condition. [Surface tension of water = 7.2 x 10^-3 N/m]

Ans: 2.26 x 10^-3J

A capillary tube of 0.3 m diameter is placed vertically inside a liquid of density 800 Kgm^-3, surface tension 5 x 10^-4 Nm^-1 and angle of contact 30°. Calculate the height to which the liquid rises in the capillary tube.

Ans: 7.2 x 104 m 

Calculate the work done in breaking a drop of water of 2mm diameter into million droplets of same size. The surface tension of water is 72x10^-3Nm^-1.

Ans: 8.9 x10^-6J

An iceberg having volume of 2.06 litre floats in seawater of density 1.03 gm/ cm^-3 with a portion of 224 CC above the surface. Calculate the density of ice.

Ans: 918kg/m³

A boy can lift a maximum load of 250 N of water. How many litres of mercury of density 13600 kgm^-3 he can lift in an identical vessel? 

Ans: 1.838 L 

A string supports a solid iron object of mass 200gm totally immersed in a liquid of specific gravity 0.9. Calculate the tension in the string if the density of iron is 8000 kg m^-3.

Ans: 1.775N

Two drops of same liquid of same radius are falling through air with steady velocity of 2.0 ms^-1. If the two drops coalesce what would be the terminal velocity?

Ans: 3.17ms^-1

Castor oil at 20°C has a coefficient of viscosity 2.42 Ns/m² and density 940 kg/m³. Calculate the terminal velocity of steel ball of radius 2.00 mm falling under gravity in the oil, taking density of steel as 7800 kg/m³.

Ans: 0.025 m/sec

Eight spherical raindrops of equal size are falling vertically through air with a terminal velocity of 0.15 m/s. What would be the terminal velocity, if they coalesce to form a big drop?

Ans: 0.6 m/sec

Calculate the magnitude, and direction of the terminal velocity of an air bubble of radius 1 mm passing through an oil of viscosity 0.2 Nsm^-2 and specific gravity 0.9 if the density of air is 1.29 Kgm^-3.

Ans: -0.0099 m/sec

Three spherical raindrops of equal size are falling vertically through air with a terminal velocity of 0.150 m/s. What would be the terminal velocity if these three drops were to coalesce to form a larger spherical drop?

Ans: 0.31 ms^-1

Calculate mass of an aeroplane with the wings of area 55m² flying horizontally. The velocity of air above and below the wings is 155 m/s and 140 m/s respectively.

Ans: 1.57x104 Kg

Eight spherical rain drops of the same mass and radius are falling down with a terminal speed of 5 cms^-1. If they coalesce to form one big drop, what will be its terminal speed?

Ans: 0.2 m/s