Question

when a capillary tube of radius 0.45mm is deep into water the level inside the capillary tube rises to a height of 3cm above the surface of water calculate the surface tension of water of its angle of contact is zero and density is 1 gm/cm'3
g=9.8​

Answer 1

Answer:

The surface tension of the liquid is 6.615 × 10⁻³ N/m

Explanation:

Given,

• Rise in capillary tube(h) = 3 cm = 3×10⁻² m
• Radius of capillary tube(r) = 0.45 mm = 0.45×10⁻³ m
• Acceleration due to gravity(g) = 9.8 m/s²
• Density of water(ρ) = 1 g/cm³ = 10³ kg/m³
• Angle of contact(θ) = 0°

We have to find the surface tension(T)

The rise in the capillary tube is given by,

h = 2Tcosθ/rρg

∴ T = hrρg/2 cosθ

⇒ T = (3 × 10⁻³ × 0.45 × 10⁻³ × 10³ × 9.8) / (2 × cos0°)

⇒ T = (13.23 × 10⁻³) / (2 × 1)

⇒ T = 6.615 × 10⁻³ N/m

∴ The surface tension of the liquid is 6.615 × 10⁻³ N/m