Discussion Forum

A uniform capillary tube of inner radius r is dipped vertically in to a beaker filled with water. The water rises  to a height  h in the capillary tube above the water surface in the beaker. The surface tension of the water is $\sigma$ . The angle of contact between water and the wall of the capillary tube is θ . Ignore the mass of water in the meniscus. Which of the following statements is (are)  true ?

Answer:

Explanation:

$h=\frac{2\sigma\cos\theta}{r\rho g}$

$(a)   \rightarrow  h\alpha\frac{1}{r}$

 (b) h depends upon  $\sigma$

(c)   If lift is going up with  constant acceleration

    $g_{eff}= (g+a)\Rightarrow h= \frac{2\sigma \cos\theta}{r\rho (g+a)}$

    It means h decreases.

(d)  h is proportional $\cos\theta$