Question -
Answer -
Take case (a):
The length of the liquid film supported by the weight, l =40 cm = 0.4 cm
The weight supported by the film, W = 4.5 × 10–2 N
A liquid film has two free surfaces.
∴Surfacetension
In all the three figures, the liquid is the same. Temperature isalso the same for each case. Hence, the surface tension in figure (b) andfigure (c) is the same as in figure (a), i.e., 5.625 × 10–2 N m–1.
Since the length of the film in all the cases is 40 cm, the weightsupported in each case is 4.5 × 10–2 N.