Step 1: Water rises h = 3.00 cm in a capillary tube of radius r = 0.50 mm. Find the surface tension T of water (ρ = 1000 kg/m³, g = 9.81 m/s², contact angle θ ≈ 0°). Step 2: Use T = r·h·ρ·g/(2·cos θ). With cos 0° = 1: T = (0.50×10⁻³)(3.00×10⁻²)(1000)(9.81)/2. Step 3: Numerator: 0.50×10⁻³ × 3.00×10⁻² = 1.50×10⁻⁵; × 1000 = 1.50×10⁻²; × 9.81 = 0.1472. Step 4: Divide by 2: T = 0.0736 N/m. Step 5: Compare with the accepted value 0.0728 N/m at 20°C — agreement within ~1%. Result: T ≈ 0.0736 N/m. Note how a narrower tube (smaller r) gives a taller column, since h ∝ 1/r.