PQRS is a rectangular frame of copper wire shown in figure the side RS of the frame is movable. If a soap film is formed on it then what is the diameter of the wire to maintain equilibirum (given surface tension of soap solution `=0.045N//m` and density of copper `=8.96xx10^(3)kg//m^(3))`

Explanation

Force due to surface tension = weight of wire `implies`
`2Tl=mg=pi^(2)ldgimpliesr=sqrt((2T)/(pidg))`
`impliesr=sqrt((2xx0.045)/(3.14xx8.96xx10^(3)xx9.8))=0.57mm`
`:.` Required diameter `d=2r=1.14mm`