The liquid (mercury) meniscus in a capillary tube will be convex if the angle of contact is

If a liquid wets a surface,is its angle of contact acute or obtuse?

If $S_1, S_2$ and $S_3$ are the tensions at the liquid-air,solid-air,and solid-liquid interfaces respectively,and $\theta$ is the angle of contact at the solid-liquid interface,then:

The raincoats are made waterproof by coating them with a material,which ............

Given below are two statements: One is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A)$: Clothes containing oil or grease stains cannot be cleaned by water wash.
Reason $(R)$: Because the angle of contact between the oil/grease and water is obtuse.
In the light of the above statements,choose the correct answer from the options given below.

If a capillary tube is dipped into a liquid and the levels of the liquid inside and outside are the same,then the angle of contact is ...... $^o$.