Radioactive decay — Paper 1 · A Level Physics 9702

40 Radon 222 Rn decays by α− and β−emission to bismuth 214 Bi . 86 83 For the decay of each nucleus of radon, how many α− and β−particles are emitted? α−particles β−particles A 1 1 B 2 1 C 1 2 D 2 2

1 marks

Answer: B

This question in 9702/11 Oct/Nov 2006

38 A detector is exposed to a radioactive source. Fluctuations in the count-rate are observed. What do these fluctuations indicate about radioactive decay? A It is random. B It is spontaneous. C It is exponential. D It is non-linear.

1 marks

Answer: A

This question in 9702/11 May/June 2007

40 A radioactive nucleus is formed by β-decay. This nucleus then decays by α-emission. Which graph of proton number Z plotted against nucleon number N shows the β-decay followed by the α-emission? A B 236 236 N N 234 234 232 232 230 230 88 90 92 94 88 90 92 94 Z Z C D 236 236 N N 234 234 232 232 230 230 88 90 92 94 88 90 92 94 Z Z

1 marks

Answer: B

This question in 9702/11 May/June 2008

40 A 238 U nucleus decays in two stages to a 234 Pa nucleus. 92 91 What was emitted in these two stages? A α + β B α + γ C β + β D β + γ

1 marks

Answer: A

This question in 9702/11 Oct/Nov 2008

37 Nuclear decay is both spontaneous and random. When the count rate of a radioactive isotope is measured, the readings fluctuate. Which row describes what the fluctuations demonstrate? spontaneous random nature nature A no no B no yes C yes no D yes yes

1 marks

Answer: B

This question in 9702/11 May/June 2009

39 The calcium nuclide 42 Ca is formed by beta decay. 20 What are the nucleon (mass) number and proton (atomic) number of the unstable nuclide that underwent beta decay to form the calcium nuclide? nucleon number proton number A 41 19 B 41 21 C 42 19 D 42 21

1 marks

Answer: C

This question in 9702/11 May/June 2009

38 The grid shows a number of nuclides arranged according to the number of protons and the number of neutrons in each. A nucleus of the nuclide Li 8 decays by emitting a β-particle. 3 What is the resulting nuclide? number of protons 4 A B 3 6 3Li 7 3Li 8 3Li 2 3 2He 4 2He C D 1 1 1H 2 1H 0 1 2 3 4 5 6 number of neutrons

1 marks

Answer: A

This question in 9702/11 May/June 2010

40 The following represents a sequence of radioactive decays involving two α-particles and one β-particle. α α β 217At V W X 85 What is the nuclide X? A 213 At B 215 77 I r C 209 Pb D 217 T l 85 82 81 Space for working

1 marks

Answer: C

This question in 9702/11 May/June 2010

39 The following represents a sequence of radioactive decays involving two α-particles and one β-particle. α α β 217At V W X 85 What is the nuclide X? A 213 At B 215 77 I r C 209 Pb D 217 T l 85 82 81

1 marks

Answer: C

This question in 9702/13 May/June 2010

40 The grid shows a number of nuclides arranged according to the number of protons and the number of neutrons in each. A nucleus of the nuclide Li 8 decays by emitting a β-particle. 3 What is the resulting nuclide? number of protons 4 A B 3 6 3Li 7 3Li 8 3Li 2 3 2He 4 2He C D 1 1 1H 2 1H 0 1 2 3 4 5 6 number of neutrons Space for working

1 marks

Answer: A

This question in 9702/13 May/June 2010

40 A counter recording radioactive decays from a radioactive source gives the following counts in equal intervals of time. time / min counts 0–10 424 10–20 395 20–30 413 30–40 363 40–50 366 50–60 294 60–70 301 70–80 253 80–90 212 What can be deduced from these readings? A that radioactivity is random and that the half-life is 90 minutes B that radioactivity is random and that the half-life is uncertain C that radioactivity is spontaneous and that the half-life is 90 minutes D that radioactivity is spontaneous and that the half-life is uncertain Space for working

1 marks

Answer: B

This question in 9702/12 Oct/Nov 2010

38 Which nuclear equation shows the beta decay of a nucleus of argon (Ar) into potassium (K)? A 44 Ar → 40 K + He 4 21 19 2 B 40 Ar → 40 K + e 0 1 20 19 C 40 Ar → 40 K + 0 e 18 19 − 1 D 40 Ar → 40 K + γ 0 0 19 19

1 marks

Answer: C

This question in 9702/13 Oct/Nov 2010

39 Uranium-238, 238 U , decays by α-emission into a daughter product which in turn decays by 92 β-emission into a grand-daughter product. What is the grand-daughter product? A 234 Th B 234 Pa C 234 U D 230 Th 90 91 9 2 90

1 marks

Answer: B

This question in 9702/11 May/June 2011

40 Uranium-238, 238 U , decays by α-emission into a daughter product which in turn decays by 92 β-emission into a grand-daughter product. What is the grand-daughter product? A 234 Th B 234 Pa C 234 U D 230 Th 90 91 9 2 90 Space for working

1 marks

Answer: B

This question in 9702/13 May/June 2011

40 A nucleus of the nuclide 241 Pu decays by emission of a β-particle followed by the emission of an 94 α-particle. Which nucleus is formed? A 239 Np B 239 Pa C 237 Np D 237 U 93 91 93 92 Space for working

1 marks

Answer: C

This question in 9702/12 Oct/Nov 2011

39 Nuclear decay is both spontaneous and random in nature. Which row gives the correct experimental evidence for these properties? spontaneous nature of decay random nature of decay A the decay rate is not affected by the decay rate is not affected by pressure temperature B the decay rate is not affected by the rate at which radiation is received pressure at a counter fluctuates C the decay rate is not affected by the decay rate is not affected by temperature pressure D the rate at which radiation is received the decay rate is not affected by at a counter fluctuates pressure

1 marks

Answer: B

This question in 9702/12 May/June 2012

40 Radon 222 Rn is the start of a decay chain that forms bismuth 214 Bi by alpha and beta emission. 86 83 For the decay of each nucleus of radon, how many α−particles and β−particles are emitted? α−particles β−particles A 1 1 B 2 1 C 1 2 D 2 2 Space for working

1 marks

Answer: B

This question in 9702/12 May/June 2012

38 A class of students used dice to simulate radioactive decay. After each throw, those dice showing a ‘6’ were removed. The graph shows the results. 100 number of 80 dice remaining 60 40 20 0 0 2 4 6 8 10 number of throws of the dice What could the scatter of points about the best-fit curve represent for actual radioactive decay? A background count not being taken into account B more than one type of radiation being present C the random nature of radioactive decay D the spontaneous nature of radioactive decay Space for working

1 marks

Answer: C

This question in 9702/11 Oct/Nov 2012

40 In a radioactive decay series, three successive decays each result in a particle being emitted. The first decay results in the emission of a β-particle. The second decay results in the emission of an α-particle. The third decay results in the emission of another β-particle. β α β P Q R S Nuclides P and S are compared. Which statement is correct? A P and S are identical in all respects. B P and S are isotopes of the same element. C S is a different element of lower atomic number. D S is a different element of reduced mass. Space for working

1 marks

Answer: B

This question in 9702/11 Oct/Nov 2012

39 What remains constant during β-emission from a number of identical nuclei in a substance? A energy of the β-particles B neutron number of the nuclei C nucleon number of the nuclei D proton number of the nuclei Space for working

1 marks

Answer: C

This question in 9702/13 Oct/Nov 2012

40 The graph of neutron number against proton number represents a sequence of radioactive decays. nucleus X 134 neutron number 133 132 131 nucleus Y 130 129 81 82 83 84 85 proton number Nucleus X is at the start of the sequence and, after the decays have occurred, nucleus Y is formed. What is emitted during the sequence of decays? A one α-particle followed by one β-particle B one α-particle followed by two β-particles C two α-particles followed by two β-particles D two β-particles followed by one α-particle Space for working

1 marks

Answer: B

This question in 9702/13 Oct/Nov 2012

40 An actinium nucleus has a nucleon number of 227 and a proton number of 89. It decays to form a radium nucleus, emitting a beta particle and an alpha particle in the process. What are the nucleon number and the proton number of this radium nucleus? nucleon number proton number A 223 87 B 223 88 C 224 87 D 225 86 Space for working

1 marks

Answer: B

This question in 9702/12 May/June 2013

38 Scientists investigating the count rate from a radioactive source observed that the count rate fluctuates. What do these fluctuations imply about the nature of radioactive decay? A It involves atomic nuclei. B It is predictable. C It is random. D It is spontaneous.

1 marks

Answer: C

This question in 9702/13 May/June 2013

40 Plutonium-239 ( 239 Pu ) decays by emitting α-radiation. 94 Which nuclide is formed from one of these decay reactions? (The product nuclides are represented by X.) A 235 X B 237 X C 239 X D 239 X 92 92 93 95 Space for working

1 marks

Answer: A

This question in 9702/11 Oct/Nov 2013

40 Plutonium-239 ( 239 Pu ) decays by emitting α-radiation. 94 Which nuclide is formed from one of these decay reactions? (The product nuclides are represented by X.) A 235 X B 237 X C 239 X D 239 X 92 92 93 95 Space for working

1 marks

Answer: A

This question in 9702/12 Oct/Nov 2013

38 In 2002, two-proton radioactive decay of an isotope of iron, 45 Fe, was observed. 26 What could be the resulting product? A 43 Fe B 43 Cr C 45 Cr D 47 Ni 26 24 24 28

1 marks

Answer: B

This question in 9702/11 May/June 2014

40 The grid shows a number of nuclides arranged according to the number of protons and the number of neutrons in each. A nucleus of the nuclide Li 8 decays by emitting a β-particle. 3 What is the resulting nuclide? 4 A B number of protons 3 6 3 Li 7 3 Li 8 3 Li 2 3 2 He 4 2 He C D 1 1 1 H 2 1 H 0 1 2 3 4 5 6 number of neutrons Space for working

1 marks

Answer: A

This question in 9702/11 May/June 2014

39 An isotope of thorium has a nucleon number of 232 and a proton number of 90. It decays to form another isotope of thorium with a nucleon number of 228. How many alpha particles and beta particles are emitted by a nucleus of thorium during this decay? alpha particles beta particles A 0 4 B 1 0 C 1 2 D 2 1

1 marks

Answer: C

This question in 9702/13 May/June 2014

39 The isotope 222 Rn decays in a sequence of emissions to form the isotope 206 Pb. At each stage 86 82 of the decay sequence, it emits either an α-particle or a β-particle. What is the number of stages in the decay sequence? A 4 B 8 C 16 D 20

1 marks

Answer: B

This question in 9702/11 Oct/Nov 2014

39 The isotope 222 Rn decays in a sequence of emissions to form the isotope 206 Pb. At each stage 86 82 of the decay sequence, it emits either an α-particle or a β-particle. What is the number of stages in the decay sequence? A 4 B 8 C 16 D 20

1 marks

Answer: B

This question in 9702/12 Oct/Nov 2014

40 The nuclide 222 Rn decays in a sequence of stages to form the nuclide 206 Pb . 86 82 Four of the nuclides formed in the sequence are α-particle emitters. The others are β-particle emitters. How many nuclides formed in the decay sequence are β-particle emitters? A 2 B 4 C 8 D 12

1 marks

Answer: B

This question in 9702/11 May/June 2015

39 A radioactive substance contains a number of identical nuclei that emit β-particles. Which property of these nuclei remains unaltered by the emission? A charge B neutron number C nucleon number D proton number

1 marks

Answer: C

This question in 9702/12 May/June 2015

40 A uranium-238 nucleus, 238 U , undergoes nuclear decays to form uranium-234, 234 U . 92 92 Which series of decays could give this result? A emission of four β-particles B emission of four γ-rays C emission of one α-particle and two β-particles D emission of two α-particles and eight β-particles

1 marks

Answer: C

This question in 9702/12 May/June 2015

37 Radioactive decay is random. What is meant by the term random? A The decay of a nucleus can be predicted. B The decay of a nucleus is unaffected by pressure. C The decay of a nucleus is unaffected by temperature. D The nucleus has a constant probability of decay per unit time.

1 marks

Answer: D

This question in 9702/11 Oct/Nov 2015

40 The diagram shows part of a radioactive decay chain in which the nuclide thorium-232 decays by α-emission into radium-228. This nuclide is also unstable and decays by β-emission into a nuclide of actinium. This process continues. α β Y α 232Th 228Ra XAc 228Th 224Z 90 88 89 90 What are X, Y and Z? X Y Z A 228 α Th B 228 β Ra C 232 α Th D 232 β Ra

1 marks

Answer: B

This question in 9702/11 Oct/Nov 2015

39 A material contains a radioactive isotope that disintegrates solely by the emission of α-particles at a rate of 100 s–1. Which statement about this material is correct? A The number of atoms in the material diminishes at a rate of 100 s–1. B The number of neutrons in the material diminishes at a rate of 100 s–1. C The number of nucleons in the material diminishes at a rate of 400 s–1. D The number of protons in the material diminishes at a rate of 100 s–1.

1 marks

Answer: C

This question in 9702/12 Oct/Nov 2015

40 A radioactive nucleus emits an α-particle or a β-particle, creating a product nucleus. Which decay process could create the product nucleus stated? radioactive nucleus decay product nucleus A 226 Ra α 224 Rn 88 86 B 238 U α 242 Pu 92 94 C 228 Ra β 228 Fr 88 87 D 231 Th β 231 Pa 90 91

1 marks

Answer: D

This question in 9702/12 Oct/Nov 2015

38 A sample of an isotope emits β– particles. The emitted β– particles have a range of energies. What must also be emitted? A antineutrinos B neutrinos C antineutrons D neutrons

1 marks

Answer: A

This question in 9702/12 Feb/March 2016

39 A nucleus of magnesium decays into a nucleus of sodium by emitting a β+ particle. The decay is represented by the equation shown. 23 Mg → Na P + 0 β 12 Q + 1 What are the values of P and Q? P Q A 22 11 B 22 13 C 23 11 D 23 13

1 marks

Answer: C

This question in 9702/12 Feb/March 2016

40 Thorium-234 ( 234 Th) decays by β– emission into a daughter product which in turn decays by a 90 further β– emission into a granddaughter product. Which letter in the diagram represents the granddaughter product? A B 92 91 proton 90 number 89 C D 88 232 233 234 235 236 nucleon number

1 marks

Answer: B

This question in 9702/12 Feb/March 2016

38 A nitrogen-13 nucleus 13 N undergoes beta decay. 7 In the equations below, ν and represent a neutrino and antineutrino respectively and γ represents a photon of gamma radiation. Which equation represents this decay? A 13 N → 13 C + β– + + γ 7 6 B 13 N → 13 C + β– + ν + γ 7 6 C 13 N → 13 C + β+ + + γ 7 6 D 13 N → 13 C + β+ + ν + γ 7 6

1 marks

Answer: D

This question in 9702/13 May/June 2016

39 Radon 222 Rn is the start of a decay chain that forms bismuth 214 Bi by α and β– emission. 86 83 For the decay of each nucleus of radon, how many α particles and β– particles are emitted? α particles β– particles A 1 1 B 2 1 C 1 2 D 2 2

1 marks

Answer: B

This question in 9702/13 May/June 2016

40 In a radioactive decay series, three successive decays each result in a particle being emitted. The first decay results in the emission of a β– particle. The second decay results in the emission of an α particle. The third decay results in the emission of another β– particle. β– α β– P Q R S Nuclides P and S are compared. Which statement is correct? A P and S are identical in all respects. B P and S are isotopes of the same element. C S is a different element of lower atomic number. D S is a different element of reduced mass.

1 marks

Answer: B

This question in 9702/11 Oct/Nov 2016

40 In a radioactive decay series, three successive decays each result in a particle being emitted. The first decay results in the emission of a β– particle. The second decay results in the emission of an α particle. The third decay results in the emission of another β– particle. β– α β– P Q R S Nuclides P and S are compared. Which statement is correct? A P and S are identical in all respects. B P and S are isotopes of the same element. C S is a different element of lower atomic number. D S is a different element of reduced mass.

1 marks

Answer: B

This question in 9702/13 Oct/Nov 2016

39 A nucleus of sodium-21, 21 Na , decays to form a new nucleus containing 10 protons 11 and 11 neutrons. Which leptons are emitted from the sodium-21 nucleus during the decay? A a positron and an antineutrino B a positron and a neutrino C an electron and an antineutrino D an electron and a neutrino

1 marks

Answer: B

This question in 9702/12 Feb/March 2017

39 A radioactive nucleus is formed by β– decay. This nucleus then decays by α-emission. Which graph of nucleon number N plotted against proton number Z shows the β– decay followed by the α-emission? A B 236 236 N N 234 234 232 232 230 230 88 90 92 94 88 90 92 94 Z Z C D 236 236 N N 234 234 232 232 230 230 88 90 92 94 88 90 92 94 Z Z

1 marks

Answer: B

This question in 9702/11 May/June 2017

37 A nucleus of uranium-238, 238 U , decays in a series of steps to form a nucleus of lead-206, 92 206 Pb , as shown. 82 238 U → … → 206 Pb 92 82 An α-particle or a β– particle is emitted during each step. What is the total number of β– particles that are emitted? A 6 B 8 C 10 D 16

1 marks

Answer: A

This question in 9702/13 May/June 2017

39 The nuclear equation shown has a term missing. 14 C → 14 N + 0 1 + … β 6 7 − What is represented by the missing term? A an antineutrino B an electron C a neutrino D a positron

1 marks

Answer: A

This question in 9702/13 May/June 2017

39 The diagram shows a sequence of radioactive decays involving three α-particles and a β– particle. α β– α α 237 N p Q R S T 93 What is nuclide T? A 225 Ra B 231 Ra C 225 Th D 229 Th 88 88 90 90

1 marks

Answer: A

This question in 9702/12 Oct/Nov 2017

39 A nucleus of neptunium-236 contains 93 protons and 143 neutrons. This nucleus decays with the emission of an α-particle. The nucleus formed then emits a β– particle. Which diagram shows the changes in the number P of protons and the number N of neutrons in these nuclei? A B 146 146 N N 144 144 142 142 140 140 138 138 90 92 94 96 90 92 94 96 P P C D 146 146 N N 144 144 142 142 140 140 138 138 90 92 94 96 90 92 94 96 P P

1 marks

Answer: D

This question in 9702/12 Feb/March 2018

40 What is the correct equation for β+ decay? A neutron → proton + electron + electron antineutrino B neutron → proton + electron + electron neutrino C proton → neutron + positron + electron antineutrino D proton → neutron + positron + electron neutrino

1 marks

Answer: D

This question in 9702/11 May/June 2018

39 A nucleus emits a β– particle. What is the change to the proton number and to the nucleon number of the nucleus? proton number nucleon number A –1 +1 B 0 –1 C +1 –1 D +1 0

1 marks

Answer: D

This question in 9702/11 Oct/Nov 2018

40 Which word equation represents β+ decay? A proton → neutron + electron + electron antineutrino B proton → neutron + electron + electron neutrino C proton → neutron + positron + electron antineutrino D proton → neutron + positron + electron neutrino

1 marks

Answer: D

This question in 9702/12 Feb/March 2019

38 A nucleus of francium-221 ( 221 Fr) decays into a nucleus of bismuth-209 ( 209 Bi) in several steps. 87 83 Which particles could be emitted? A 2 α-particles and 4 β– particles B 2 α-particles and 4 β+ particles C 3 α-particles and 2 β– particles D 3 α-particles and 2 β+ particles

1 marks

Answer: C

This question in 9702/12 May/June 2019

39 An unstable nucleus of an element decays by emitting an α-particle or a β– particle to become a nucleus of a different element. This nucleus is also unstable and also emits an α-particle or a β– particle. The process continues until an isotope of the original element is produced. What is the minimum possible number of these particles emitted? A 2 B 3 C 4 D 5

1 marks

Answer: B

This question in 9702/11 Oct/Nov 2019

39 The equation represents the decay of a nucleus X to a nucleus Y. A ZX → Z 1 Y A + p + q − What are particles p and q? p q A β– particle neutron B β– particle proton C β+ particle antineutrino D β+ particle neutrino

1 marks

Answer: D

This question in 9702/12 Feb/March 2020

39 An unstable nucleus goes through successive decays to become a final, stable nucleus. The initial nucleus and the final nucleus are isotopes of each other. How many α and β– particles could have been emitted during the decay sequence? particle α β– A 1 0 B 1 2 C 2 0 D 2 1

1 marks

Answer: B

This question in 9702/12 May/June 2020

39 The figure shows part of a chart of nuclides where neutron number is plotted against proton number. An unstable nuclide X decays by emitting an α-particle. Which nuclide is formed by the decay of nuclide X? 147 neutron C number 146 X 145 D 144 B 143 142 A 141 140 91 92 93 94 95 96 proton number

1 marks

Answer: B

This question in 9702/12 Feb/March 2021

39 A uranium-238 nucleus, 238 U, undergoes a series of nuclear decays to form uranium-234, 234 U. 92 92 Which series of decays could give this result? A emission of four – particles B emission of four -rays C emission of one -particle and two – particles D emission of two -particles and eight – particles

1 marks

Answer: C

This question in 9702/11 Oct/Nov 2021

39 A nucleus of neptunium-236 contains 93 protons and 143 neutrons. This nucleus decays with the emission of an -particle. The nucleus formed then emits a – particle. Which diagram shows the changes in the number P of protons and the number N of neutrons in these nuclei? A B 146 146 N N 144 144 142 142 140 140 138 138 90 92 94 96 90 92 94 96 P P C D 146 146 N N 144 144 142 142 140 140 138 138 90 92 94 96 90 92 94 96 P P

1 marks

Answer: D

This question in 9702/13 Oct/Nov 2021

39 A nucleus X is radioactive and decays into a nucleus Y. X and Y are isotopes of the same element. Which combination of particles could have been emitted during the decay process? A 1 -particle and 1 – particle B 1 -particle and 2 – particles C 2 -particles and 1 – particle D 2 -particles and 2 – particles

1 marks

Answer: B

This question in 9702/12 Feb/March 2022

38 Carbon-14 decays into nitrogen-14 by emitting a – particle. Which statement explains why the – particles are emitted with a range of different kinetic energies? A The carbon-14 nuclei have slightly different masses. B The emitted – particles have a range of different masses. C The energy released in the decay process is different for each carbon-14 nucleus that decays. D The energy released in the decay process is shared between the nitrogen-14 nucleus, a – particle and an antineutrino.

1 marks

Answer: D

This question in 9702/11 May/June 2022

39 A nucleus of a radioactive element emits an -particle, then a – particle and then another – particle. Which statement describes the final element that is produced? A It is a different element of higher proton number than the original element. B It is a different element of lower nucleon number than the original element. C It is an isotope of the original element. D It is the same element as the original element but with a different proton number.

1 marks

Answer: C

This question in 9702/11 May/June 2022

39 A nucleus of 238 U decays in stages by emitting -particles and – particles, eventually forming a 92 nucleus of 206 Pb. 82 How many -particles and how many – particles are emitted during the decay chain? -particles – particles A 8 6 B 8 10 C 16 6 D 16 22

1 marks

Answer: A

This question in 9702/11 Oct/Nov 2022

39 A nucleus X undergoes + decay. The products are a nucleus Y with proton number Z, a + particle and another particle P. X  ZY + + + P What is particle P and what is the proton number of nucleus X? proton number P of nucleus X A antineutrino Z – 1 B antineutrino Z + 1 C neutrino Z – 1 D neutrino Z + 1

1 marks

Answer: D

This question in 9702/13 Oct/Nov 2022

39 Americium-241 is a radioactive nuclide used in smoke detectors. It undergoes α-decay to form nuclide X. This decay may be represented by the equation shown. 241 95Am → A Z X + α What are the values of A and Z? A Z A 237 93 B 239 91 C 241 94 D 241 96

1 marks

Answer: A

This question in 9702/12 Feb/March 2023

39 A uranium nucleus has 92 protons and 143 neutrons. The nucleus emits a total of 3 -particles and 4 – particles to form nucleus X. How can nucleus X be represented? A 131 X B 219 X C 223 X D 223 X 90 87 82 90

1 marks

Answer: D

This question in 9702/11 May/June 2023

39 Which statement about – decay is correct? A A neutron changes to a proton in the nucleus and an electron and an antineutrino are emitted. B A neutron changes to a proton in the nucleus and an electron and a neutrino are emitted. C A proton changes to a neutron in the nucleus and an electron and an antineutrino are emitted. D A proton changes to a neutron in the nucleus and an electron and a neutrino are emitted.

1 marks

Answer: A

This question in 9702/13 May/June 2023

39 When a sample of a radioactive isotope decays by -particle emission, the -particles emitted have a single discrete energy. When a sample of a radioactive isotope decays by – particle emission, the – particles emitted have a continuous range of energies. What is the explanation for this? A An antineutrino is emitted with a – particle but not with an -particle. B An antineutrino is emitted with an -particle but not with a – particle. C The -particles have much more energy than the – particles. D The – particles have much more energy than the -particles.

1 marks

Answer: A

This question in 9702/13 Oct/Nov 2023

39 An unstable nucleus of an element decays by emitting an -particle or a – particle to become a nucleus of a different element. This nucleus is also unstable and emits an -particle or a – particle. The process continues until an isotope of the original element is produced. What is the minimum possible number of these particles emitted? A 2 B 3 C 4 D 5

1 marks

Answer: B

This question in 9702/12 Feb/March 2024

38 A radioactive sample decays by emitting – particles. The energy released in the decay process is the same for each nucleus that decays, but the – particles emitted have a continuous range of kinetic energies. Which statement explains why the – particles are emitted with a continuous range of kinetic energies? A Some of the energy released is given to the remaining nucleons in the nucleus. B Some of the energy released is taken by an emitted antineutrino. C Some of the energy released is used to create the – particle. D Some of the energy released is used to create a new nucleon.

1 marks

Answer: B

This question in 9702/11 May/June 2024

38 Nucleus P has 144 neutrons and 93 protons. Nucleus P is unstable and undergoes -decay to form nucleus Q. Nucleus Q then undergoes – decay to form nucleus R. Nucleus P is represented by point P on the graph. Which point on the graph represents nucleus R? 146 145 number of neutrons P 144 C 143 B 142 A D 141 140 90 91 92 93 94 95 96 proton number

1 marks

Answer: A

This question in 9702/13 May/June 2024

39 The isotope fluorine-18, 18 F, undergoes + decay to form a stable isotope. 9 How many neutrons are there in a nucleus of the stable isotope? A 7 B 8 C 9 D 10

1 marks

Answer: D

This question in 9702/11 Oct/Nov 2024

40 An isotope of boron decays to beryllium by + emission. Which particle is emitted in addition to the + particle? A antineutrino B electron C neutrino D neutron

1 marks

Answer: C

This question in 9702/12 Oct/Nov 2024

40 A magnesium nucleus 23 Mg decays by emitting two particles. 12 The resulting nucleus is sodium 23 Na. 11 Which two particles are emitted? A -particle, antineutrino B + particle, antineutrino C – particle, neutrino D + particle, neutrino

1 marks

Answer: D

This question in 9702/13 Oct/Nov 2024

39 What is the change to the quark composition of a nucleus that takes place during + decay? A down to antiup B down to up C up to antidown D up to down

1 marks

Answer: D

This question in 9702/12 Feb/March 2025

39 Which statement explains why alpha-particles have discrete energies, but beta-particles have a continuous range of energies? A Beta-particles have a much smaller mass than alpha-particles which means beta-particles can be emitted with a larger range of velocities. B Only alpha-particles experience repulsion from the nucleus which is dependent on the number of protons in the nucleus. C Only beta-particles are emitted with another lepton and some energy is transferred to the other lepton. D Only the energy of alpha-particles is discrete because the composition of alpha-particles is always the same.

1 marks

Answer: C

This question in 9702/11 May/June 2025

40 A nucleus of carbon-11 contains 6 protons and 5 neutrons. The nucleus of carbon-11 decays by + emission. What is the total number of up and down quarks in the product of the decay of this nucleus? up quarks down quarks A 15 18 B 16 17 C 17 16 D 18 15

1 marks

Answer: B

This question in 9702/12 May/June 2025

40 The nucleus of a radioactive isotope of an element emits an -particle. The daughter nucleus then emits a – particle and then the daughter nucleus of that reaction emits another – particle. Which statement describes the final nuclide that is formed? A It is a different isotope of the original element. B It is a nuclide of a different element of higher proton number. C It is a nuclide of the same element but with different proton number. D It is identical to the original nuclide.

1 marks

Answer: A

This question in 9702/13 May/June 2025

38 A nucleus W of a radioactive isotope emits a – particle and forms nucleus X. Nucleus X emits an -particle to form nucleus Y. Nucleus Y emits a – particle to form nucleus Z. Which statement about Z is correct? A Z is a nucleus of a different element from W and has a higher nucleon number. B Z is a nucleus of a different element from W and has a lower nucleon number. C Z is a nucleus of the same element as W and has a higher nucleon number. D Z is a nucleus of the same element as W and has a lower nucleon number.

1 marks

Answer: D

This question in 9702/14 May/June 2025

39 A nucleus of magnesium-23 decays to form a nucleus of sodium-23, emitting a + particle and particle X. What is particle X? A an antineutrino B an electron C a neutron D a neutrino

1 marks

Answer: D

This question in 9702/12 Oct/Nov 2025

40 A nucleus of 238 U decays in stages by emitting -particles and – particles, eventually forming a 92 nucleus of 206 Pb. 82 How many -particles and how many – particles are emitted during the decay chain? -particles – particles A 8 6 B 8 10 C 16 6 D 16 22

1 marks

Answer: A

This question in 9702/12 Oct/Nov 2025

38 The diagram shows a sequence of radioactive decays involving three -particles and a – particle. 237Np Q R S T 93 What is nuclide T? A 225 Ra B 231 Ra C 225 Th D 229 Th 88 88 90 90

1 marks

Answer: A

This question in 9702/13 Oct/Nov 2025

39 A nucleus of polonium, 214 Po, decays by emitting an -particle to become a nucleus of lead. 84 The nucleus of lead is also unstable and decays by emitting a – particle to form a nucleus of bismuth which then decays by emitting a – particle to produce a nucleus X. What is the number of neutrons in nucleus X? A 126 B 128 C 130 D 210

1 marks

Answer: A

This question in 9702/14 Oct/Nov 2025