Department of Pre-University Education, KarnatakaPUC Karnataka Science Class 11

# It is Said that a Liquid Rises Or is Depressed in Capillary Due to the Surface Tension. If a Liquid Neither Rises Nor Depresses in a Capillary, Can We Conclude that the Surface Tension of the Liquid - Physics

Short Note

It is said that a liquid rises or is depressed in capillary due to the surface tension. If a liquid neither rises nor depresses in a capillary, can we conclude that the surface tension of the liquid is zero?

#### Solution

No, we cannot conclude the surface tension to be zero solely by the fact that the liquid neither rises nor falls in a capillary.
The height of the liquid inside a capillary tube is given by $h = \frac{2T\cos\theta}{r\rho g}$ . From the equation, we see that the height (h) of the liquid may also be zero if the contact angle  $\theta$  between the liquid and the capillary tube is  ${90}^0 \text{ or } {270}^0$ .

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#### APPEARS IN

HC Verma Class 11, 12 Concepts of Physics 1
Chapter 14 Some Mechanical Properties of Matter
Short Answers | Q 10 | Page 297