Question:
Two mercury drops (each of radius r) merge to form a bigger drop. The surface energy of the bigger drop, if the surface tension is T, is
Two mercury drops (each of radius r) merge to form a bigger drop. The surface energy of the bigger drop, if the surface tension is T, is
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Surface energy is proportional to surface area.
Updated On: Mar 18, 2026
- 25π r² T
- 4π r² T
- 2π r² T
- 28π r² T
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The Correct Option is A
Solution and Explanation
Step 1: Volume conservation: 2· (4)/(3)π r³ = (4)/(3)π R³ R = 3√(2)r
Step 2: Surface energy: E = 4π R² T = 4π ( 3√(2)r )² T = 25π r² T
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