If a glass rod is dipped in mercury and withdrawn out,the mercury does not wet the rod because

Show that the force exerted by a fluid at rest is perpendicular to its contact surface.

When the surface of one liquid is in contact with another liquid or the surface of a solid,on what does the surface tension depend?

$A$ drop of oil is placed on the surface of water. Which of the following statements is correct?

Water does not wet an oily glass because

Explain why:
$(a)$ The angle of contact of mercury with glass is obtuse,while that of water with glass is acute.
$(b)$ Water on a clean glass surface tends to spread out while mercury on the same surface tends to form drops. (Put differently,water wets glass while mercury does not.)
$(c)$ Surface tension of a liquid is independent of the area of the surface.
$(d)$ Water with detergent dissolved in it should have small angles of contact.
$(e)$ $A$ drop of liquid under no external forces is always spherical in shape.