InterviewSolution
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InterviewSolution
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Find the capillary pressure (a) in mercury droplets of diameter `d = 1.5 mu m` , (b) inside a soap bubble diameter `d = 3.0 mm` if the surface tension of the soap water solution is `alpha = 45 mN//m`. |
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Answer» (a) `Delta p = alpha ((1)/(d//2) + (1)/(d//2)) = (4 alpha)/(d)` =`(4 xx 490 xx 10^-3)/(1.5 xx 10^-6) (N)/(m^2) = 1.307 xx 10^6 (N)/(m^2) = 12` atmosphere (b) The soap bubble has two surfaces so `Delta p = 2 alpha ((1)/(d//2) + (1)/(d//2)) = (8 alpha)/(d)` =`(8 xx 45)/(3 xx 10^-3) xx 10^-3 = 1.2 xx 10^-3` atmosphere. |
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