Angle of Contact — Prelims Questions

A liquid drop on a solid surface forms a convex meniscus. Which of the following statements is true regarding the angle of contact and the forces involved?

If the angle of contact for a liquid-solid interface is $0^circ$, what does this imply about the wetting behavior and capillary action?

Which of the following factors does NOT affect the angle of contact?

A liquid has a surface tension $\gamma = 0.072,\text{N/m}$ and forms an angle of contact of $60^circ$ with a glass capillary tube of radius $0.5,\text{mm}$. If the density of the liquid is $1000,\text{kg/m}^3$ and $g = 10,\text{m/s}^2$, what is the approximate height the liquid will rise in the capillary tube?

A liquid drop is placed on a surface. If the solid-gas interfacial tension ($\gamma_{SG}$) is $60,\text{mN/m}$, the solid-liquid interfacial tension ($\gamma_{SL}$) is $30,\text{mN/m}$, and the liquid-gas interfacial tension ($\gamma_{LG}$) is $40,\text{mN/m}$, what is the angle of contact?

When a small amount of detergent is added to water, how does it affect the angle of contact with a greasy surface and the cleaning action?