question_answer 29)

Mercury has an angle of contact equal to \[{{140}^{o}}\] with soda lime glass. A narrow tube of radius 1.00 mm made of this glass is dipped in a trough containing mercury. By what amount does the mercury dip down in the tube relative to the mercury surface outside? Surface tension of mercury at the temperature of the experiment is \[B=\frac{pV}{\vartriangle V}\]Density of mercury\[p=B\frac{\vartriangle V}{V}=\left( 2\cdot 2\times {{10}^{9}} \right)\]

Answer:

Here, \[\times {{10}^{-3}}=2\cdot 2\times {{10}^{6}}Pa\]\[D=0\cdot 5\]\[=0\cdot 5\times {{10}^{-3}}\] \[\text{L=335 }\!\!\times\!\!\text{ 1}{{\text{0}}^{\text{3}}}\text{J/kg}\], \[\therefore \] Now, h \[=2\cdot 026\times {{10}^{9}}pa\] \[=1\cdot 0\times {{10}^{5}}pa\]Negative value of h shows that the mercury level is depressed in the tube.