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The pressures inside two soap bubbles are 1.01 and 1.02 atmosphere respectively. The ratio of their volumes is

Asked in JEE Main 3rd Sept 1st Shift 2020 · Excess pressure

Answer: (3) 8:1

Step-by-step solution

Given: pressures 1.01 atm and 1.02 atm, against an outside pressure of 1 atm.

Idea: only the excess over the atmosphere is set by the curvature, so subtract first — the excesses are 0.01 atm and 0.02 atm.

For a soap bubble Δ p=(4T)/R, so (R₁)/(R₂)=(Δ p₂)/(Δ p₁)=(0.02)/(0.01)=2.

(V₁)/(V₂)=((R₁)/(R₂))³=2³.

(V₁)/(V₂)=8:1.

Why the other options are wrong

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