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Surface tension of a soap bubble is 2.0 × 10⁻² Nm⁻¹. Work done to increase the radius of soap bubble from 3.5 cm to 7 cm will be:
Take π = 22/7
- 5.76 × 10⁻⁴ J
- 0.72 × 10⁻⁴ J
- 9.24 × 10⁻⁴ J
- 18.48 × 10⁻⁴ J
Correct answer: 18.48 × 10⁻⁴ J
Solution
The work done to increase the radius of a soap bubble is calculated using the formula for work done against surface tension, which is proportional to the change in surface area. In this case, the increase in radius leads to a significant increase in surface area, resulting in the calculated work of 18.48 × 10⁻⁴ J.
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