Discussion Forum

When one end of the capillary is dipped in water, the height of the water column is 'h'. The upward force of 105 dyne due to surface tension is balanced by the force due to the weight of water column. The inner circumference  of the capillary is (Surface tension of water = 7 x 10^-2 N/m)

Answer:

Explanation:

 Given, F= 105 dyne= 105 x 10^-5 N

 T= 7 x10^-2  N/m

As we know, circumference of the capillary  x surface tension = upward force

  $2\pi rT=F$

$2\pi r=\frac{F}{T}=\frac{105\times 10^{-5}}{7 \times 10^{-2}}=15 \times 10^{-3}m$

 = 1.5 x 10^-2 m=1.5 cm