A wire is bent in the formof a U. shape and a sider of negligible mass is connecting the two verticalslides of the U-shape. This arrangement is dipped in to soap solutiona and lifted, a thin soap film is formed in the frame. It supports a weight of 2.0xx10^(-3)N. If the length of the slider is 40 cm, what is the surface tension of the film?

A wire is bent in the formof a U. shape and a sider of negligible mass

1.	A wire is bent in the formof a U. shape and a sider of negligible mass is connecting the two verticalslides of the U-shape. This arrangement is dipped in to soap solutiona and lifted, a thin soap film is formed in the frame. It supports a weight of 2.0xx10^(-3)N. If the length of the slider is 40 cm, what is the surface tension of the film?
Answer» Solution :`W=2.0xx10^(-2)N,l=40cm=0.4m` Upward FORCE DUE to surface tesion `=Sxx2l` In equilibrium `W=Sxx2l` `S=W/(2l)=(2xx10^(-2))/(2xx0.4)=2.5xx10^(-2)Nm^(-1)`