De Broglie wavelength of a thermal neutron at temperature T:

De Broglie wavelength of a thermal…

Answer: h/sqrt(3mkT).

A h/sqrt(2mKT)
B h/sqrt(mkT)
C h/sqrt(3mkT)
D h × sqrt(2mkT)

Correct answer: C. h/sqrt(3mkT)

Explanation: Thermal energy = (3/2)kT = p²/2m. p = sqrt(3mkT). lambda = h/sqrt(3mkT).

Comparison of the Thomson model and the Rutherford model of the atom: in the Thomson plum pudding model alpha particles pass almost straight through a diffuse positive sphere, while in the Rutherford model a concentrated central nucleus deflects some alpha particles through large angles, with the lower panels showing the alpha particle source and gold foil and the observed result of wide-angle scattering

The Geiger–Marsden alpha-scattering result: a few alpha particles bounce back at large angles, which rules out Thomson’s diffuse model and demands a tiny, massive, positively charged nucleus. Image: Kurzon, CC BY 3.0, via Wikimedia Commons.

Concept context

Thomson's plum-pudding model, Rutherford's nuclear model from alpha-scattering, Bohr's postulates and hydrogen spectrum, spectral series (Lyman to Pfund), Rydberg formula, and limitations of each model.

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De Broglie wavelength of a thermal neutron at temperature T:

Concept context

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