本题目来源于试卷: Nuclear & Quantum Physics E.3 Radioactive Decay，类别为 IB物理学
[单选题]
During experiments obso t39wnn x ))t( gnv2yqpb,oye)i1i6 berving beta decays, it was seen that the energy spectru 53 ix 48ie*bhzwoe5lky,e qga24+li om of the beta particles is4b+y54olwi2z * ,k ega oe3eqhxil 85i continuous and momentum conservation was violated in beta decays. This provided evidence for the existence of:
A. Nuclear energy levels
B. Atomic energy levels
C. Neutrinos
D. Positrons
参考答案: C
本题详细解析:
Explanation: In beta decays, the continuous energy spectra and apparent violation of the law of conservation of momentum let to the postulation of the existence of the neutrino as a particle that could account for the anomaly. Therefore the answer is C. Nuclear energy levels are evidenced by the discrete energies of alpha particle emissions along with the discrete energies of gamma emissions caused by the nucleus transitioning to lower energy states. Absorption and emission spectra give evidence of atomic energy levels. Positrons were first observed in cloud chamber experiments involving cosmic rays.
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