Q)
(chatquestion)...energy spent in this process.
Tempaer
Solution
4
R
As volume of water remains constant, so
R3
Increase in surface area AA = n (4ar) - 4TR? = 47(n/3 -1) R2
= 4n(100 – 1)10-6
.. Energy spent = TAA = 4n x 99 x 10-6 x 72 x 10-3 = 89.5 x 106 J
BEGINNER'S BOX-6
A stick of length 4 cm is floating on the surface of water. If one side of it has surface tension of 80 dyne/cm and on
the other side by keeping a piece of camphor the surface tension is reduced to 60 dyne/cm, then find the resultant
Torce (in dyne) acting on the stick. (resultant felce
ene side)
%3D
on
A thin wire ring of radius 1m is situated on the surface of a liquid. If the excess force required to lift it upwards
(before the liquid film breaks) from the liquid surface is 8 N. calculate the surface tension of liquid?
A circular frame made of 20 cm long thin wire is floating on the surface of water. The surface tension of water
3.
is 70 dyne/cm. Calculate the required excess force to separate this frame from water ?
A metallic wire of density d floats horizontally in water. Find out the maximum radius of the wire so that the
wite
may not sink. (surface tension of water
T)
A rectangular film of liquid is 5 cm long and 3 cm wide. If the work done in increasing its area to
9 cm x5 cm is 6 x 104 joule, find the surface tension of the liquid ?
5....(1 Ques btado plz)
...
