The surface tension of a soap bubble is 0.03 N m⁻¹. The work done in increasing the diameter of the bubble from 2 cm to 6 cm is απ×10⁻⁴ J. The value of α is (take π=3.14)

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(3) 1.92. Given: T=0.03 N m⁻¹, diameters 2 cm and 6 cm, so r₁=0.01 m and r₂=0.03 m. A soap bubble in air has two surfaces, inner and outer, so its total area is 2(4π r²)=8π r². Work done =T Δ A=8π T(r₂²-r₁²). W=8π(0.03)(9×10⁻⁴-1×10⁻⁴)=8π(0.03)(8×10⁻⁴)=1.92π×10⁻⁴ J. Hence α=1.92.

The surface tension of a soap bubble is 0.03 N m⁻¹. The work done in increasing the diameter of the bubble from 2 cm to 6 cm is απ×10⁻⁴ J. The value of α is (take π=3.14)

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