A vertical vapillary with inside diameter `0.50 mm` is submergeed into water so that the length of its part emerging outside the water surface is equal to `25 mm`. Find the radius of curvature of the meniscus. Surface tension of water is `73xx10^(-3)N//m`.

Explanation

In the capillary tube, the water should rise to a height
`h=(2T)/(rrhog)`
Here
`T=73xx10^(-3)N.m`
`r=(0.50mm)/2=0.25xx10^(-3)m`
`rho=10^(3)kg//m^(3)`
`:. H=(2xx73xx10^(-3))/(0.25xx10^(-3)xx10^(3)xx9.8)=59xx10^(-3)m=59m`
Now `hgth'`, i.e., length is outside water surrface
Therefore radius of meniscusgtradius of capillary `r`.
If `R` is the radius of meniscus, then we have
`(2T)/R=h'rhog`
or `R=(2T)/(h'rhog)`
Here `h'=25mm=25xx10^(-3)m`
`:.R=(2xx73xx10^(-3))/(25xx10^(-3)xx10^(3)xx9.8)=0.6xx10^(-3)m=0.6m`