A glass capillary tube of internal radius r =0.25 mm is immersed in water. The top end of the tube projected by 2 ~cm above the surface of the water. At what angle does the liquid meet the tube? Surface tension of water =0.7 ~N / m

Step-by-step solution

Water wets glass and so the angle of contact is zero. For full rise, neglecting the small mass in the meniscus aligned 2 T &= r ² ~h g h = 2 ~T r g [ water wets glass, =0^ ] &= 2 007 0.25 10⁻³ 1000 9.8 aligned As the tube is only 2 ~cm above the water and so, water will rise by 2 ~cm and meet the tube at an angle such that, aligned 2 r & T = r² h^ g & 2 T =h^ r g &= h^ r g 2 T &= 2 10⁻² 0.25 10⁻³ 1000 9.8 2 0.07 aligned The liquid will meet the tube at an angle, 70^