A vertical capillary tube with inside diameter `0.50 mm` is submerged 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 a capillary with diameter `d = 0.5 mm` water will rise to a height
`(2 alpha)/(rho g r) = (4 alpha)/(rho g d)`
=`(4 xx 73 xx 10^-3)/(10^3 xx 9.8 xx 0.5 xx 10^-3) = 59.6 mm`
Since this greater than the height `(= 25 mm)` of the tube, menscus of radius `R` will be formed at the top of the tube, where
`R = (2 alpha)/(rho gh) = (2 xx 73 xx 10^-3)/(10^3 xx 9.8 xx 25 xx 10^-3) ~~0.6 mm`.
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