A soap bubble of surface tension 0.04 N / m is blown to a diameter of 7 cm . If (15000- x ) μ J of work is done in blowing it further to make its diameter 14 cm , then the value of x is \ \ \ \ . ( π=22 / 7 )

Physics · Mechanical Properties of Matter

JEE Main 2026 — 24 January, Evening Shift — Question 48

A soap bubble of surface tension $0.04 \mathrm{~N} / \mathrm{m}$ is blown to a diameter of 7 cm . If $(15000-\mathrm{x}) \mu \mathrm{J}$ of work is done in blowing it further to make its diameter 14 cm , then the value of x is $\_\_\_\_$ . ( $\pi=22 / 7$ )

Answer: 11304

Numerical answer — enter this value.

Step-by-step solution

$\mathrm{W}=\Delta \mathrm{u}$

\begin{aligned} & =S \times\left(8 \pi r_{2}^{2}-8 \pi r_{1}^{2}\right) & =0.04 \times 2 \times \frac{22}{7}(147) \times 10^{-4} & W=3696 \times 10^{-6} J & 3696=15000-x & x=11304 \mu J \end{aligned}

Answer key and solution verified before publishing.

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Exam: JEE Main 2026
Paper: 24 January, Evening Shift
Subject: Physics
Chapter: Mechanical Properties of Matter
Topic: Surface Tension and Surface Energy