Liquid Meniscus in Capillarity
A liquid in capillary tube shows three different types of Meniscus that are,
- Concave Meniscus
- Convex Meniscus
- Plane Meniscus
Concave Meniscus
If the pressure below the meniscus is less than the pressure above the meniscus then we say the concave meniscus occurs. The concave meniscus is observed in water and glass. Suppose the pressure above meniscus is PA and the pressure below the meniscus is PB then the excess pressure is,
PA – PB = 2T/r
where, r is the radius of the meniscus.
Convex Meniscus
If the pressure below the meniscus is greater than the pressure above the meniscus then we say the convex meniscus occurs. The convex meniscus is observed in mercury and glass. Suppose the pressure above meniscus is PA and the pressure below the meniscus is PB then the excess pressure is,
PB – PA = 2T/r
where, r is the radius of the meniscus.
Plane Meniscus
The plane meniscus is observed when the difference between the above and the below meniscus is zero, i.e. pressure above meniscus and pressure below meniscus is equal and excess pressure is zero. And thus no capillary action is observed.
The concave, convex, and plane meniscus is shown in the image added below,
Capillary Action
Capillary Action in Physics is the action of the liquid in the capillary tubes. Capillary tubes, which are narrow cylindrical tubes, have very small diameters. It is observed that the liquid in the capillary either rises (or) decreases in relation to the level of the surrounding liquid when these tiny tubes are submerged in a liquid. The action of these liquids is called the capillary action and it is an important phenomenon in physics.
Capillary action is caused by the intermolecular attraction of the water molecules and the adhesive force between the capillary walls and the liquid. In this article, we will learn about Capillary Action, the Capillary Action Formula, Its derivation, examples, and others in detail.
Table of Content
- What Is Capillary Action?
- Capillary Action Formula
- Forces in Capillary Action
- Liquid Meniscus in Capillarity
- Difference between Concave, Convex and Plane Meniscus
- Applications of Capillarity
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