Question

Due to capillary action, a liquid will rise in a tube if angle of contact is:

A) Acute

B) Obtuse

C) $ {90^ \circ } $ 

D) Zero

Answer 1

Hint: An ascent formula describes the liquid which wets the glass of the tube and the angle of contact in it is acute angle. Thus. $\cos \theta $ Is positive and the liquid rises upward in the tube. The term capillary is not limited to direction. 

Complete step by step answer:

According to ascent formula the height/depth (h) through which a liquid will rise/fall in a capillary tube of radius (r) is given by, 

$h = \dfrac{{2S\cos \theta }}{{r\rho g}} $ 

Where $S$ is the surface tension, $\rho $ is the density of the liquid and $\theta $ is the angle of contact.

If $\theta  < {90^ \circ } \Rightarrow \cos \theta  > 0 \Rightarrow h > 0 \Rightarrow $ The liquid will rise when contact angle is acute.

If $\theta  > {90^ \circ } \Rightarrow \cos \theta  < 0 \Rightarrow h < 0 \Rightarrow $The liquid will fall when contact angle is obtuse.

Therefore option (A) is the right answer.

Additional Information:

Capillary action is defined as the moment of water within the spaces of a porous martial force due to the forces of surface tension, adhesion and cohesion. In other words we can also describe the capillary action as a movement of liquid through long other martial agents and opposite forces such as gravity. The best example that defines capillary action in water which includes water moving up a straw or glass tube, moving through a plant, moving through a cloth tower.

Note: Capillary action is a source of renewable energy that is by glowing water to climb through capillaries it evaporates once it reaches the top and then condensate and draw back down to the bottom spinning a turbine on its way to create energy moreover capillary action makes electricity.