What is the energy spent in blowing a soap bubble of radius 7cm? What additional work will be done in furthur blowing it to double radius. Surface tension=30dyne/cm
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3 Answers
106Energy of a soap bubble = 2T.4Î R2 [as T=E/A and bubble has two surfaces..]
So. energy spent in blowing a soap bubble of radius 7 cm = 2*30*4*22/7*49 = 36960 erg = 0.003696 J
Energy of a soap bubble of double radius = 2T.4Î (2R)2 = 147840 erg = 0.014784 J
So, further work done = E2-E1 = 110880 erg = 0.011088 J
