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Calculate the work done in blowing a soap bubble of radius 4 cm. The surface tension of the soap solution is 25 × 10-3 N/m. |
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Answer» Data : r = 4 cm = 4 × 10-2 m, T = 25 × 10-3 N/m Initial surface area of soap bubble = 0 Final surface area of soap bubble = 2 × 4πr2 Increase in surface area = 2 × 4πr 2 The work done = surface tension x increase in surface area = T × 2 × 4πr2 = 25 × 10-3 × 2 × 4 × 3.142 × (4 × 10-2)2 = 1.005 × 10-3 J |
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