Consider a small surface area of 1 mm² at the top of a mercury drop of radius 4.0 mm. Find the force exerted on this area to) by the air above it (b) by the mercury below it and (c) by the mercury surface in contact with it. Atmospheric pressure = 1.0 × 10⁵ Pa and surface tension of mercury = 0.465 N m^-1. Neglect the effect of gravity. Assume all numbers to be exact.

A 5.0 cm long straight piece of thread is kept on the surface of water. Find the force with which the surface on one side of the thread pulls it Surface tension of water = 0.076 N m^-1.

Find the excess pressure inside (a) a drop of mercury of radius 2 mm (b) a snap bubble of radius 4 mm and (c) an air bubble of radius 4 mm formed inside a tank of water. Surface tension of mercury, soap solution and water are 0.465 N m^-1, 0.03 N m^-1 and 0.076 N m^-1 respectively.

The capillaries shown in figure (14-E4) have inner radii 0.5 mm, 1.0 mm and 1.5 mm respectively. The liquid in the beaker is water. Find the heights of water level in the capillaries. The surface tension of water is 7.5 × 10^-2 N m^-1.

The lower end of a capillary tube is immersed in mercury. The level of mercury in the tube is found to be 2 cm below the outer level. If the same tube is immersed in water, up to what height will the water rise in the capillary?