Mechanical Properties of Fluids
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Question : 29
Total: 31
Mercury has an angle of contact equal to 140° 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 liquid surface outside? Surface tension of mercury at the temperature of the experiment is 0.465 N m – 1 = 13.6 × 10 3 k g m – 3
Solution:
Here, angle of contact, θ = 140 °
r = 1 mm = 10 – 3 m
Surface tension,T = 0.465 N m – 1
density of mercury,r = 13.6 × 10 3 k g m – 3
Now using the formula,h =
,
[Here,cos 140 ° = − 0.7660 ]
= − 5.34 × 10 − 3 m
= − 5.34 mm
Here negative sign shows that the mercury level is depressed in the tube relative to the mercury surface outside.
Surface tension,
density of mercury,
Now using the formula,
[Here,
Here negative sign shows that the mercury level is depressed in the tube relative to the mercury surface outside.
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