Question

The liquid meniscus in a capillary tube will be convex, if the angle of contact is :

• A. greater than ${90}^o$
• B. less than ${90}^o$
• C. equal to ${90}^o$
• D. equal to zero

Answer 1

The correct option is A greater than ${90}^o$

A convex meniscus occurs when the particles in the liquid have a stronger attraction to each other(cohesion) than to the material of the container.
It occurs when mercury is placed in a glass capillary.

The types of meniscus are shown in the figure.

In a convex meniscus, the angle of contact is greater than ${90}^{\circ }$, which is angle between tangent to the liquid surface and the capillary surface, inside the liquid.