Question

The upward force of 105 dyne due to surface tension is balanced by the force due to the weight of the water column and 'h' is the height of water in the capillary. The inner circumference of the capillary is ______.

(surface tension of water = 7 × 10^-2 N/m)

Options

• 1 cm

• 2.5 cm

• 1.5 cm

• 3 cm

Answer 1

The upward force of 105 dyne due to surface tension is balanced by the force due to the weight of the water column and 'h' is the height of water in the capillary. The inner circumference of the capillary is 1.5 cm.

Explanation:

T = 7 × 10^-2 N/m = 70 dyne/cm

2πRT = 105

2πR = `105/70=21/14=3/2=1.5  "cm"`