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A soap bubble of radius 1 cm is enclosed inside a larger soap bubble of radius 3 cm. Determine the radius (in cm) of a single soap bubble that would sustain the same pressure difference as that existing between the interior of the small bubble and the exterior of the large bubble.
- 4/3
- 3/4
- 1/2
- 2
Correct answer: 3/4
Solution
The total pressure drop from inside the small bubble to outside the large bubble is the sum of the excess pressures of each, since pressure is additive across the two interfaces.
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