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MHT CET 2026 (15 Apr, Shift 1) · Surface Energy & Work Done

Surface Energy & Work Done question from MHT CET 2026 (15 Apr, Shift 1)

Q4MHT CET 2026 · 15 APR · SHIFT 1Medium

Surface Energy & Work Done

A soap bubble of radius R is blown. After heating the solution, a second bubble of radius 2R is blown. The work required to blow the second bubble in comparison to that required for the first bubble is

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Answer: (a)

$W = 8\pi R^2 T$ , so for radius $2R$ at the same $T$ , $W$ would be exactly 4 times.
Surface tension decreases with rise in temperature, so $T' < T$ .
Hence $W_2 = 8\pi(2R)^2 T' < 4W_1$ , but only slightly.
So the answer is (a) slightly less than 4 times.

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