Question

If a 5 cm long capillary tube with 0.1 mm internal diameter, open at both ends, is slightly dipped in water having surface tension 75 dyne/cm, state whether: water will rise up to the upper end of capillary

Answer 1

$T=75dyne/㎝,r=0.005㎝,\rho =1ℊ/㎤,\theta =0°$

$h=\frac{2T\cos \theta }{r\rho g}=\frac{2\times 75\times \cos 0°}{0.005\times 1\times 981}㎝=30.58㎝$

Length of capillary$=5㎝$

Because tube is of insufficient length, the water will rise up to the upper end of the tube.