Q1(b). Inclined capillary

Answer in brief

The distance along the capillary is 1.22 m, assuming complete wetting.

Key points

• Take the contact angle as zero and g=9.81 m s⁻². Convert r=10⁻⁵ m, ρ=850 kg m⁻³ and γ=0.036 N m⁻¹.
• Balance the upward surface-tension force and the weight of the vertical column: 2π rγcos θ=π r²hρ g. Thus h=2γ/(ρ gr)=0.8635 m.
• The requested length is l=h/sin 45°=1.221 m. If the contact angle is nonzero, multiply this value by cos θ.