InterviewSolution
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InterviewSolution
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A wire ring of 4 cm radius on the surface of a liquid and then raised. If surface tension of the tension of the liquid is `78.8 dyn e//cm`, find the pull (in g wt) required to raise the ring more before the film breaks than it is afterwards. |
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Answer» Here, `S=78.8 dyn e//cm , r=4cm` As the liquid touches the ring both along the inner and outer circumference, so force on the ring due to surface tension is `F= 2 xx 2 pi r xx S = 4 pi r S` `=4 xx 22/7 xx 4 xx 78.8 dyn e` `= 4 xx 22/7 xx (4 xx 78.8)/(980) g wt = 4.04 g wt`. |
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