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Question
Calculate the work done in blowing a soap bubble to a radius of 1 cm. The surface tension of soap solution is 2.5 × 10-2 N/m.
Solution
Given:
T = 2.5 × 10-2 N/m, r1 = 0 m, r2 = 1 cm = 10-2 m, W = ?
Formula:
W = 2T dA = 2T × 4π`(r_2^2 - r_1^2)`
∴ W = `2 xx 2.5 xx 10^-2 xx 4pi xx 10^-4`
∴ W = 6.283 × 10-5 J
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