Question

When we observe the level of water in a capiilary, we note down the level of the tangent to the meniscus inside the water.

Answer 1

1. When water rises in a capillary tube, its surface forms a concave meniscus due to surface tension.
2. Since the surface is curved, its level cannot be read directly. Therefore, the height is measured at the lowest point of the concave meniscus by drawing or imagining a tangent there.
3. This gives the correct and definite level of water in the capillary tube.