Question

Water rises in a straight capillary tube upto a height of $5\text{cm}$ when held vertical in a water beaker. If the capillary tube is bent as shown in figure, then the height of water column in it will be

• A. $5\text{cm}$
• B. Less than $5\text{cm}$
• C. More than $5\text{cm}$
• D. None of the above

Answer 1

The correct option is A $5\text{cm}$

Capillary rise is independent of the shape of capillary tube, if radius of the capillary tube does not change.

since, capillary rise is
$h=\frac{2T\cos \theta }{r\rho g}$
For the given material of tube and water combination, the contact angle$\left(\theta \right)$ will be same throughout, and if cross-sectional area of tube remains same i.e $r=\text{constant}$.

$\Rightarrow$Capillary rise$\left(h\right)$ will remain same.
$\therefore h=5\text{cm}$