A rectangular film of liquid is extended from (4 cm$\times$ $2$ $\mathrm{cm}$) to \((4 ~\text{cm}\times 5 ~\text{cm})\). If the work done is $3\times {10}^{-4}$ J, the value of the surface tension of the liquid is: 

A rectangular film of liquid is extended from \((4~\text{cm} \times 2~\text{cm})\) to \((5~\text{cm} \times 4~\text{cm}).\) If the work done is \(3\times 10^{-4}\) J, the value of the surface tension of the liquid is:
1. \(0.250\) Nm^–1
2. \(0.125\) Nm^–1
3. \(0.2\) Nm^–1
4. \(8.0\) Nm^–1