An electron, a proton, an \(\alpha\)-particle and a hydrogen atom are moving with the same kinetic energy. The associated de-Broglie wavelength will be longest for –

Q.1 (vi) An electron, a proton, an \(\alpha\)-particle and a hydrogen atom are moving with the same kinetic energy. The associated de-Broglie wavelength will be longest for –

A. proton

B. electron

C. hydrogen atom

D. \(\alpha\)-particle

Doubtly Asked 28 Oct 2026 Board exam · March 2025 hsc 12th Save WhatsApp Report

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Answer: B. electron

Answer: (b) electron

For a particle of kinetic energy \(K\), \(p = \sqrt{2mK}\), so \(\lambda = \dfrac{h}{\sqrt{2mK}} \propto \dfrac{1}{\sqrt{m}}\) for the same \(K\). The electron has the smallest mass of the four, so its de Broglie wavelength is the longest.

Doubtly AI · 28 Oct 2026 AI-verified · Oct 2026 Report

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An electron, a proton, an \(\alpha\)-particle and a hydrogen atom are moving with the same kinetic energy. The associated de-Broglie wavelength will be longest for –

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