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The surface tension of a soap solution is 30 dyne/cm. A soap bubble made from this solution has a radius of 1cm. What is the work done in doubling the radius of the soap bubble? |
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Answer» Solution :For a spap BUBBLE, we multiply the area by 2, as there are TWO free SURFACES T = dw/dA `therefore dw = T XX dA xx 2 = T xx 4PI (4r^2 - r^2) xx 2` `dw = 24pir^2T = 24 xx 3.142 xx 1^2 xx 30` = 2262 ergs. |
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