Question

Two capillary tubes of radius 0.5 mm and 1 mm when dipped in a liquid of surface tension 49 dyne / cm vertically , it is observed that the liquid level difference is found to be 1.25 cm in the tubes . Then the density of the liquid will be `(theta = 0^(@))`
A. `0.08` g/cc
B. `0.8` g/cc
C. `0.04`g/cc
D. `0.4`g/c

Answer 1

Correct Answer - B
`h_(1)-h_(2) = (2tcos theta )/(rho g )[ 1/(r_(1))-1/(r_(2))]`
` rho = (2T cos theta )/(g(h_(1)-h_(2)))[1/r_(1)-1/(r_(2))]`
`= (2xx 49 xx cos (0))/(980 xx 1.25 )[1/(0.05)-1/(0.1)]`
` = 1/ 10 xx 4/5 xx (20 - 10 ) = ( 4xx 10)/50 `
= 0.8 g/cc .