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Physics Chapter 14 : Topic 5
Alpha and Beta Energy Spectra
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The energy spectrum of alpha $\mathbf{(\alpha)}$ particles is:
Reasoning: Alpha particles are emitted with specific energies because nuclear energy levels are quantized.
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The energy spectrum of beta $\mathbf{(\beta)}$ particles is:
Reasoning: Beta particles are emitted with a continuous range of energies due to sharing energy with neutrinos / antineutrinos.
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Alpha particles have discrete energies because:
Reasoning: Nuclear energy levels are quantized, so alpha particles are emitted with specific energy values.
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The continuous energy distribution of beta particles was explained by the discovery of:
Reasoning: Neutrinos or antineutrinos carry away variable amounts of energy, giving beta particles different energies.
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Why do beta particles from the same radioactive source not all have the same energy?
Reasoning: The electron and antineutrino share the available energy in varying proportions.
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In $\mathbf{\beta}^{\mathbf{-}}$ decay, the total energy released is shared between:
Reasoning: The available decay energy is divided between the emitted electron and electron antineutrino.
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If no neutrino were emitted during beta decay, the beta particles would be expected to have:
Reasoning: Without neutrino emission, the decay energy would go entirely to the beta particle, giving a fixed energy.
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The presence of antineutrinos in $\mathbf{\beta}^{\mathbf{-}}$ decay explains:
Reasoning: Antineutrinos take away different amounts of energy, leaving beta particles with different energies.
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Which radiation shows a line spectrum due to fixed energies?
Reasoning: Alpha particles are emitted with discrete energies, producing characteristic lines.
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A detector measures alpha particles from a radioactive source. It finds only a few specific energies. This indicates:
Reasoning: Specific alpha energies result from transitions between fixed nuclear energy levels.
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In $\mathbf{\beta}^{\mathbf{-}}$ decay, the missing energy originally observed was later explained by:
Reasoning: The antineutrino carries away the missing energy and momentum.
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The energy spectrum of beta particles is a:
Reasoning: Beta particles can have any energy from nearly zero up to a maximum value.
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During $\mathbf{\beta}^{\mathbf{+}}$ decay, the continuous energy spectrum occurs because energy is shared between:
Reasoning: In $\mathbf{\beta}^{\mathbf{+}}$ decay, the positron and electron neutrino share the decay energy.
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A beta particle with maximum possible energy is produced when:
Reasoning: The beta particle receives maximum energy when the neutrino carries away minimum energy.
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A beta particle with very low energy is produced when:
Reasoning: Energy is shared between beta particle and neutrino; if neutrino takes more, beta particle gets less.
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Which statement about alpha decay is correct?
Reasoning: Alpha decay involves a two-body process producing fixed energy values.
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Which statement about beta decay is correct?
Reasoning: Beta decay involves the nucleus, beta particle, and neutrino / antineutrino.
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The continuous beta spectrum provides evidence for:
Reasoning: The continuous spectrum was evidence that another particle was carrying away energy.
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Alpha decay produces a fixed energy because:
Reasoning: Alpha decay is mainly a two-body decay, so energy division is fixed.
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Beta decay differs from alpha decay because:
Reasoning: The neutrino / antineutrino causes beta particles to have a range of energies.
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A radioactive source emits particles with energies $\mathbf{4\ MeV}$, $\mathbf{6\ MeV}$, and $\mathbf{8\ MeV}$ only. The particles are most likely:
Reasoning: Discrete energy values are characteristic of alpha emission.
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A radioactive source emits electrons having energies from $\mathbf{0}$ to $\mathbf{2.0\ MeV}$. These electrons are:
Reasoning: Beta particles have a continuous energy range.
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The maximum energy of beta particles represents:
Reasoning: Maximum beta energy occurs when the neutrino / antineutrino carries almost no energy.
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Which decay process gives a continuous energy spectrum?
Reasoning: Beta decay involves three bodies, allowing variable energy sharing.
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The energy of an emitted alpha particle depends mainly on:
Reasoning: Alpha energy is determined by the difference between nuclear energy states.
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Why does beta radiation not show sharp energy lines like alpha radiation?
Reasoning: Variable energy sharing prevents a single beta energy value.
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In $\mathbf{\beta}^{\mathbf{-}}$ decay, if the electron receives $\mathbf{70\%}$ of the available energy, the remaining energy is carried by:
Reasoning: The remaining energy is carried away by the antineutrino.
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The continuous beta spectrum does NOT violate conservation of energy because:
Reasoning: The neutrino / antineutrino accounts for the energy and momentum balance.
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Which comparison is correct?
Reasoning: Alpha particles have discrete energies, while beta particles have a continuous range.
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The emission of an antineutrino during $\mathbf{\beta}^{\mathbf{-}}$ decay changes the beta particle energy because:
Reasoning: The energy division between electron and antineutrino produces different beta energies.
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