Question

A water film is made between two straight parallel wires of length $10cm$ each, and at a distance of $0.5cm$ from each other. If the distance between the wires is increased by $1mm$, how much work will be done? Surface tension of water$=7.2\times {10}^{-2}$ N/m.

Answer 1

$W=T\left(\Delta A\right)$
$=(7.2\times {10}^{-2})\left[2\left(0.1\right)\left({10}^{-3}\right)\right]$
$=1.44\times {10}^{-5}$ J