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Unit 1: Thermal, nuclear and electrical physics

Quick questions on Nuclear physics and radioactivity: QCE Physics Unit 1 Year 11

8short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.

What are isotopes?
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Same ZZ, different NN. E.g., 12^{12}C, 13^{13}C, 14^{14}C.
What is alpha?
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Emit helium nucleus 24^4_2He. Mass number drops 4, atomic number drops 2. Range: cm in air; stopped by paper.
What is beta-minus?
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Neutron →\to proton + electron + antineutrino. Atomic number increases by 1; mass number unchanged. Range: metres in air; stopped by aluminium.
What is gamma?
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High-energy photon from excited nucleus. Mass and atomic numbers unchanged. Highly penetrating; lead/concrete shielding.
What is half-life as deterministic?
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Individual decay is random.
What is q1?
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Define isotope and identify the decay particle that does not change the mass number. [2 marks]
What is q2?
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Complete the alpha decay equation 88226Ra→?Rn+α^{226}_{88}\text{Ra} \rightarrow ?\text{Rn} + \alpha. State the mass and charge of the alpha particle. [3 marks]
What is q3?
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A 40 MBq40 \text{ MBq} source of cobalt-6060 (T1/2=5.3 yearsT_{1/2} = 5.3 \text{ years}) is purchased for radiotherapy. (a) Calculate the activity remaining after 15.9 years15.9 \text{ years}. (b) Cobalt-6060 decays by beta-minus then gamma.

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