Question

Water rises in a capillary tube to a certain height such that the upward force due to surface tension is balanced by 63 × 10^-4 N force due to the weight of the water. The surface tension of water is 7 × 10^-2 N/m. The inner diameter of the capillary tube is nearly ______.

(π = 22/7)

Options

• 7 × 10^-2 m

• 9 × 10^-2 m

• 6.3 × 10^-1 m

• 3 × 10^-2 m

Answer 1

Water rises in a capillary tube to a certain height such that the upward force due to surface tension is balanced by 63 × 10^-4 N force due to the weight of the water. The surface tension of water is 7 × 10^-2 N/m. The inner diameter of the capillary tube is nearly 3 × 10^-2 m.

Explanation:

W = 2πT

`therefore2r=W/(piT)=(63xx10^-4xx7)/(22xx7xx10^-2)`

`approx 3xx10^-2  "m"`