what is the capillary rise and fall>phenomenon of capillary tube>formula>fluid mechanics>episode-16

FLUID MECHANICS
Capillarity

MY BOOK:-https://imojo.in/unitech108

• It's the phenomenon of rise and fall of the liquid surface in small tube (diameter is less than 10mm) relative to adjacent level of liquid when tube is immersed vertically downward
• The rise of liquid is known capillary rise and the fall of liquid is known as capillary depression
•  $ads={1}
• 
  

Phenomenon

• Minicus=down
• Convexity=down
• Concavity=up
• Adhesion>cohession
• Wetting liquid
• θ<90°

• Minicus=up
• Convexity=up
• Concavity=down
• Adhesion<cohession
• Non Wetting liquid
• θ>90°

$ads={2}
Note

• For water (pure) and clean glass combination θ≈0°
• For clean glass and AgNO ₃ solution θ≈90°
• For clean glass and Mercury (hg) θ≈128°, θ≈125° to 140°
• capillary rise /depression is given by H=4Tcosθ/¶gd

where,T=surface tension
θ=contact angle
d=diameter of tube
¶=density of liquid
H=capillary rise/depression left sidebar

contact form

x