- #1
leena19
- 186
- 0
Homework Statement
A glass tube is vertically suspended using a spring balance.The thickness of the glass tube is 0.4mm.Now it is lowered towards a liquid.When the lower surface of the tube touches the liquid surface,a change can be seen in the spring balance reading.
Now the tube is immersed in the liquid until the reading of the spring balance returns to its original reading.
At this stage the height of the tube immersed in the liquid is 3.67cm.If the density of the liquid is 1000kgm-3,calculate the surface tension of the liquid.
[ans:7.34*10-2]
Homework Equations
T(surface tension)=F/l
The Attempt at a Solution
l or the length the surface tension acts on = 2*pi*r + 2*pi(r+d)
where r=internal radius of the tube
r+d=external radius of the tube and d=0.4mm
F=T*l
F=2*pi*T(2r+d)When the tube just touches the liquid the scale reading increases(to S) due to surface tension forces acting down on the tube.
When the tube is immersed in the fluid,upthrust probably acts on the tube restoring the original scale reading(R) ?
But I'm not sure how this helps me find T