 The icons above show Thomson's plum-pudding model, Rutherford's nuclear model, and the $\alpha$-particle scattering experiment. Which model was proposed *to explain* the back-scattering observed in $\alpha$-particle scattering?
ASchrödinger's wave-mechanical model
BRutherford's nuclear model
CBohr's quantised-orbit model
DThomson's plum-pudding model
Answer & Solution
Correct answer: B. Rutherford's nuclear model
Rutherford proposed his nuclear model specifically to account for the small fraction of $\alpha$ particles that scattered through large angles in the gold-foil experiment. Thomson's plum-pudding model could not — it predicted only small deflections from a diffuse charge cloud. Bohr came later, building on Rutherford's nucleus by adding quantised orbits to explain spectral lines.
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