InterviewSolution
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InterviewSolution
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The radii of two air bubbles are in the ratio 4 : 5. Find the ratio of excess pressure inside them. Also compare the works done in blowing these bubbles. |
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Answer» Let the radii of two air bubbles be `r_(1) = 4 R` `r_(2) = 5 R` If the respective excess pressures are `Delta P_(1) and Delta P_(2)` Then `Delta P_(1) = (4S)/(r_(1))` `Delta P_(2) =(4S)/(r_(2))` `(Delta P_(1))/(Delta P_(2))=(r_(2))/(r_(1))=(5)/(4)` Work done in blowing the bubbles are `W_(1) = S xx 2 xx 4 pi r_(1)^(2)` `W_(2) = S xx 2 xx 4 pi r_(2)^(2)` Thus `(W_(1))/(W_(2))=((r_(1))/(r_(2)))^(2)=((4)/(5))^(2)` `=(16)/(25)` |
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