Fig, shown a thin film supporting a small weight = `4.5xx10^(-2)N`. What is the weight supported by a film of the same liquid at the same temperature in fig. explain your answer physically.

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Explanation

The length of the flim supporting the weight =40 cm
=0.4 m
`F=4.5 xx 10^(-2) N`
Surface tension, `T=F/(2l)` [the flim has two surface]
`T=(4.5 xx 10^(-2))/(2 xx 0.4)`
`=5.625 xx 10^(-2) Nm^(-1)`
Since I and temperature are same for all the cases. Therefore, the weight supported by a film of the same liquid at the same temperature in cases (b) and (c) will be `4.5 xx 10^(-2)N.`