This pressure difference across a curved liquid surface is described by the Laplace pressure formula. For a soap bubble, which has two surfaces (inner and outer), the excess pressure inside is given by ΔP = 4γ/r, where γ is the surface tension and r is the radius of the bubble. Since r is positive, ΔP is positive, meaning the pressure inside is greater than the pressure outside (atmospheric pressure).
Pressure inside a soap bubble is :
Asked in UPPCS Prelims 1995 · Topic: Physical Properties of Materials (Viscosity and Surface Tension)
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Answer: A. More than atmospheric pressure
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