Question

A glass capillary tube is lowered vertically into liquid in a vessel.
Match the column.
$\begin{array}{cc}\text{Column 1}& \text{Column 2}\\ \text{Meniscus observed}& \text{Liquid level in capillary tube}\\ \text{A) Concave}& \text{(i) Ascends}\\ \text{B) Convex}& \text{(ii) Descends}\\ \text{C) Flat}& \text{(iii) Neither ascends nor descends}\end{array}$

• A. $A\to \left(i\right);B\to \left(ii\right);C\to \left(iii\right)$
• B. $A\to \left(ii\right),B\to \left(i\right);C\to \left(iii\right)$
• C. $A\to \left(iii\right);B\to \left(ii\right);C\to \left(i\right)$
• D. None of these.

Answer 1

The correct option is A $A\to \left(i\right);B\to \left(ii\right);C\to \left(iii\right)$

We know,
For concave meniscus, contact angle $\left(\theta \right)$ is is less than ${90}^{\circ }$
Also,
For $\theta <{90}^{\circ }$, liquid level in capillary tube ascends
Similarly,
For convex meniscus, $\theta >{90}^{\circ }$
$\Rightarrow$ Liquid level in capillary tube descends.
For flat meniscus, $\theta ={90}^{\circ }$
$\Rightarrow$ Liquid level neither ascends nor descends.