Physics · Oct / Nov 2023 · Paper 41 · Question 9
0625
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The question as text
Many household smoke alarms contain a sample of the radioactive isotope americium-241 (Am).
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9(a)(i)[1]
(americium-241 has) one neutron fewer (in the nucleus)
9(a)(ii)[2]
(different) number of protons (in nucleus)
(different) number of neutrons (in nucleus)
9(b)(i)[3]
241
Am
237Np
4a
95
93
2
any two from:
95Am
237Np
4
2a
9(b)(ii)[2]
(α-particles have) more kinetic energy (than β-particles)
(α-particles have) more charge (than β-particles)
9(b)(iii)[2]
Low(er) (initial) activity OR Few emissions per unit time
so smoke detectors are not hazardous to humans OR so disposal of old detectors is cheap / easy
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