A vertical U$-$shaped wire frame has a slide wire attached

on the lower side. It is $0\mathrm{.}2$ m wide and $0\mathrm{.}1$ m high, and is

filled with a film of water. The slide wire has a weight of

$0\mathrm{.}032$ N and is in equilibrium. What is the surface tension

of the water?

$1.0\mathrm{.}04$ N m$-1$

$2.0\mathrm{.}08$ N m$-1$

$3.0\mathrm{.}16$ N m$-1$

$4.0\mathrm{.}32$ N m$-1$

$5.0\mathrm{.}032$ N m$-1$