Question

A capillary tube is placed vertically inside the beaker of water of surface tension ` 7 xx 10^(-2)` N/m and the angle of contact is `0^(@)` . The height raised by the water in capillary tube ` 7 xx 10^(-2)` m
The radius of the capillary tube is
A. `2xx10^(-4)`m
B. `0.2xx10^(-4)`m
C. `0.02xx10^(-4)`m
D. `0.002 xx 10^(-4)` m

Answer 1

Correct Answer - A
`2T cos theta = h rho gr`
`h = (2tcos(0))/(rhogr)`
` :. r = (2xx7xx10^(-2))/(10^(3)xx10xx7xx10^(-2))`
` r = 0.2 xx10^(-3)`
` = 2 xx 10^(-4)` cm