Question

What is surface energy? Establish the relation between surface tension and surface energy.

Answer 1

S=surface tension of soap Liquid

l= length of PQ

Total Inward Force on the wire $PQ$

$F=S\times 2l$

To increase surface area we have to pull wire $PQ$ outwards with for $F$

Film is stretched by small distance $x$ to position $P,Q$

To increase in Area of film $PQQ,P,$

$=a=2(l\times x)$

Work done in stretching film $F=\times Distance$

$=(s\times 2l)\times x=s\times \left(2lx\right)=s\times a$

$2lx$=increase in area =a

$l\times a$= area $o^{+}$ film Both side

Surface Energy is defined as the amount of workdone against the force of surface tension, in forming the liquid surface of a given area at a contant temprature