1. 50.1×10⁻⁴ J 2. 30.16×10⁻⁴ J 3. 5.06×10⁻⁴ J 4. 3.01×10⁻⁴ J

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

1. \(50.1\times10^{-4}\) J

2. \(30.16\times10^{-4}\) J

3. \(5.06\times10^{-4}\) J

4. \(3.01\times10^{-4}\) J

Doubtly Asked 30 Oct 2026 NEET UG 2023 Practice test neet Save WhatsApp Report

Best answer

Answer: 4. \(3.01\times10^{-4}\) J

A soap bubble has two surfaces (inner and outer), so the energy needed equals surface tension times total area \(2\times4\pi r^2\).

\(W=2\times4\pi r^2 T=8\pi(0.02)^2(0.03)=8\pi\times1.2\times10^{-5}\approx3.0\times10^{-4}\) J.

The answer is \(3.01\times10^{-4}\) J.

Doubtly AI · 30 Oct 2026 AI-generated · not yet verified Report

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