2023 Mechanical Properties of FluidsSurface Tension and Surface Energy Medium Question 8 of 34 in Mechanical Properties of Fluids

The amount of energy required to form a bubble of radius 2 cm from a soap solution is nearly: (surface tension of soap solution $=0.03\ N\,m^{-1}$)

A $50.1\times10^{-4}\ J$
B $30.1\times10^{-4}\ J$
C $5.06\times10^{-4}\ J$
D $3.01\times10^{-4}\ J$

The answer is D.

Solution

A soap bubble has two surfaces, so energy $=8\pi R^2T\approx3.01\times10^{-4}\ J$.

Surface energy of a bubble = 2 × change in surface area × surface tension $=8\pi R^2\times T=8\times3.142\times4\times10^{-4}\times3\times10^{-2}\ J$ $=30.1\times10^{-5}\ J$

Concept energy to form a soap bubble

Mechanical Properties of Fluids in past papers

34 questions from this chapter have appeared across 14 exam years.