Mercury which is spilled onto a glass surface forms ball-like shapes because____.
A. Mercury is a metal B. The cohesive force between its molecules is greater than the adhesive force between mercury and glass molecules C. The cohesive force between its molecules is less than the adhesive force between mercury and glass molecules D. The viscosity of mercury is height
Correct Answer: B
Explanation
In case of small drops of mercury, the gravitational potential energy is negligible in comparison to the potential energy due to surface tension.Consequently, to keep the drop in equilibrium, the mercury drop’s surface tends to contract so that its surface area will be the least for a sphere and the drops will be spherical.  But in the case of bigger drops of mercury, the potential energy due to gravity is predominant over the potential energy due to surface tension.Consequently, to keep equilibrium , the mercury drop tends to assume minimum potential energy as possible, the drop becomes oval in shape and lower center of gravity.
