Question

The capillaries shown in figure (14-E4) have inner radii 0.5 mm, 1.0 mm and 1.5 mm respectively. The liquid in the beaker is water. Find the heights of water level in the capillaries. The surface tension of water is `7.5xx10^-2Nm^-1`.

Answer 1

Correct Answer - A::B::C
a. `T=7.5xx10^-2N/m, costheta=1`
`(a)`. `h_A=(2Tcostheta)/(r_A.rhog)`
`=(2xx7.5xx10^-2)/(5xx10^-3xx1000xx10)`
`=3xx10^-2m=3cm`
`(b)`. `h_B=(2Tcostheta)/(r_B.rhog)`
`=(2xx7.5xx10^-2)/(5xx10^-3xx10^3xx10)`
`=15xx10^-xm=1.5cm`
c. `h_0=(2Tcostheta)/(r_Crhog)`
`=(2xx7.5xx10^-2)/(1.5xx10^-3xx10^3xx10)`
`=15/1.5xx10^-3=10^-2m=1cm`
The height of `H_2O` levle in A,B,C cappliareis are 3 cm 1.5 cm nd 1 cm respectivel.