Radioactivity — Paper 2 · IGCSE Physics 0625

38 A nucleus of a radioactive substance 218 Po undergoes an α-decay followed by a β-decay. 84 What are the nucleon (mass) number and proton (atomic) number of the nuclide formed after both decays have happened? nucleon number proton number A 214 85 B 216 85 C 214 83 D 216 83

1 marks

Answer: C

This question in 0625/22 Feb/March 2016

39 A scientist carries out an experiment using a sealed source which emits β-particles. The range of the β-particles in the air is about 30 cm. Which precaution is the most effective to protect the scientist from the radiation? A handling the source with long tongs B keeping the temperature of the source low C opening all windows in the laboratory D washing his hands before leaving the laboratory

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Answer: A

This question in 0625/22 Feb/March 2016

40 Which row describes the nature of α-particles and of γ-rays? α-particles γ-rays A helium nuclei electromagnetic radiation B helium nuclei electrons C protons electromagnetic radiation D protons electrons

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Answer: A

This question in 0625/22 Feb/March 2016

36 The diagram shows a shaded area where the direction of a magnetic field is into the page. A beam of β-particles enters the field as shown. magnetic field into the page beam of β-particles In which direction is the beam of β-particles deflected as they enter the magnetic field? A into the page B out of the page C down the page D up the page

1 marks

Answer: C

This question in 0625/21 May/June 2016

37 The arrangement shown is used to check whether the flour inside a cardboard packet is above a certain level. If it is above this level, the flour absorbs the radiation from the source so that it doesn’t reach the detector. radioactive detector source flour cardboard packet Which type of radiation is suitable to use? A α-particles only B β-particles only C either α-particles or β-particles D γ-rays only

1 marks

Answer: B

This question in 0625/21 May/June 2016

38 A nucleus of americium 243 Am emits an α-particle to form a nucleus of neptunium (Np). 95 Which equation represents this decay? A 243 Am → 247 Np + α 4 95 97 2 B 243 Am → 243 Np + α 0 95 96 - 1 C 243 Am → 243 Np + α 0 95 94 - 1 D 243 Am → 239 Np + α 4 95 93 2

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Answer: D

This question in 0625/21 May/June 2016

40 A reading is taken every 10 minutes of the number of emissions per second from a radioactive source. The table shows the readings. number of time / min emissions per second 0 800 10 560 20 400 30 280 40 200 50 140 60 100 What is the half-life of the source? A 10 min B 20 min C 40 min D 60 min

1 marks

Answer: B

This question in 0625/21 May/June 2016

36 The diagram shows a shaded area where the direction of a magnetic field is into the page. A beam of β-particles enters the field as shown. magnetic field into the page beam of β-particles In which direction is the beam of β-particles deflected as they enter the magnetic field? A into the page B out of the page C down the page D up the page

1 marks

Answer: C

This question in 0625/22 May/June 2016

37 A very important experiment increased scientists’ understanding of the structure of matter. In the experiment, particles scattered as they passed through a thin metal foil. Which particles were used, and to which conclusion did the experiment lead? particles conclusion A alpha particles matter is made up of atoms B alpha particles atoms have a very small nucleus C beta particles matter is made up of atoms D beta particles atoms have a very small nucleus

1 marks

Answer: B

This question in 0625/22 May/June 2016

39 A radioactive decay can be represented as shown. 233 Pa → 233 U 91 92 The equation is incomplete. In this decay, the nucleus changes by A absorbing a neutron. B absorbing a proton. C emitting an α-particle. D emitting a β-particle.

1 marks

Answer: D

This question in 0625/22 May/June 2016

40 The graph shows how the decay rate of a radioactive source changes with time. 4000 decay rate 3000 decays / s 2000 1000 0 0 2 4 6 8 10 time / days What will be the decay rate at 8 days? A 0 decays / s B 125 decays / s C 250 decays / s D 500 decays / s

1 marks

Answer: C

This question in 0625/22 May/June 2016

36 The diagram shows a shaded area where the direction of a magnetic field is into the page. A beam of β-particles enters the field as shown. magnetic field into the page beam of β-particles In which direction is the beam of β-particles deflected as they enter the magnetic field? A into the page B out of the page C down the page D up the page

1 marks

Answer: C

This question in 0625/23 May/June 2016

38 Which diagram represents an experiment that provided evidence for the nuclear atom? A B α-particle β-particle gold gold nucleus nucleus C D α-particle β-particle gold gold nucleus nucleus

1 marks

Answer: C

This question in 0625/23 May/June 2016

39 Sodium-24 decays to magnesium-24 according to the following equation. 24 11Na → 24 12Mg + emitted particle What is the emitted particle? A α-particle B β-particle C neutron D proton

1 marks

Answer: B

This question in 0625/23 May/June 2016

40 The reading on a detector placed near a radioactive material is 536 counts per second. The background count rate is 44 counts per second. The half-life of the radioactive material is 34 hours. What is the reading on the detector after 68 hours? A 44 counts per second B 123 counts per second C 134 counts per second D 167 counts per second

1 marks

Answer: D

This question in 0625/23 May/June 2016

39 A nucleus undergoes radioactive decay. The proton number increases by one. The nucleon number does not change. Which particle has been emitted in this decay? A a neutron B a proton C an α-particle D a β-particle

1 marks

Answer: D

This question in 0625/21 Oct/Nov 2016

40 Radioactive source S emits α-particles, β-particles and γ-rays. A detector is placed 5 cm away from S. A thin sheet of paper is placed as shown in the diagram. thin sheet of paper S detector 5 cm Which emissions from the source can be detected? A α-particles and β-particles only B α-particles and γ-rays only C β-particles and γ-rays only D α-particles, β-particles and γ-rays

1 marks

Answer: C

This question in 0625/21 Oct/Nov 2016

38 A β-particle enters a uniform magnetic field directed out of the page. uniform β-particle magnetic field out of the page In which direction is the β-particle deflected by the field? A towards the top of the page B into the page C out of the page D towards the bottom of the page

1 marks

Answer: A

This question in 0625/22 Oct/Nov 2016

39 The radioactive nucleus 214 Bi decays to another nucleus by the emission of a β-particle. 83 What is the proton number and what is the nucleon number of the nucleus formed by this decay? proton number nucleon number A 81 210 B 81 212 C 84 213 D 84 214

1 marks

Answer: D

This question in 0625/22 Oct/Nov 2016

40 Radioactive source S emits α-particles, β-particles and γ-rays. A detector is placed 5 cm away from S. A thin sheet of paper is placed as shown in the diagram. thin sheet of paper S detector 5 cm Which emissions from the source can be detected? A α-particles and β-particles only B α-particles and γ-rays only C β-particles and γ-rays only D α-particles, β-particles and γ-rays

1 marks

Answer: C

This question in 0625/22 Oct/Nov 2016

38 An α-particle enters a uniform magnetic field directed out of the page. uniform magnetic field out of the page α-particle In which direction is the α-particle deflected by the field? A into the page B out of the page C to the left D to the right

1 marks

Answer: D

This question in 0625/23 Oct/Nov 2016

39 Radioactive source S emits α-particles, β-particles and γ-rays. A detector is placed 5 cm away from S. A thin sheet of paper is placed as shown in the diagram. thin sheet of paper S detector 5 cm Which emissions from the source can be detected? A α-particles and β-particles only B α-particles and γ-rays only C β-particles and γ-rays only D α-particles, β-particles and γ-rays

1 marks

Answer: C

This question in 0625/23 Oct/Nov 2016

40 Uranium-238 is radioactive and decays to thorium-234 by the emission of a particle. 238 U → 234 Th + particle 92 90 Which particle is emitted in this process? A an α-particle B a β-particle C a neutron D a proton

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Answer: A

This question in 0625/23 Oct/Nov 2016

37 A radioactive substance emits radiation at a rate of 600 emissions per second. Four hours later, it emits radiation at a rate of 300 emissions per second. What is the half-life of the substance and what is the rate of emission after a further four hours? rate of emission after half-life / hours a further four hours / emissions per second A 2 0 B 2 150 C 4 0 D 4 150

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Answer: D

This question in 0625/22 Feb/March 2017

39 The equation represents an isotope of radium Ra decaying to an isotope of radon Rn with the emission of particle X. 226 Ra → 222 Rn + X 88 86 What is particle X? A 0 e B 1 H C 4 He D 0 1 n − 1 1 2

1 marks

Answer: C

This question in 0625/22 Feb/March 2017

40 An atomic nucleus decays by one or more radioactive decay processes. What causes the proton number to decrease by 1? A α-decay followed by β-decay B α-decay only C β-decay followed by γ-decay D β-decay only

1 marks

Answer: A

This question in 0625/22 Feb/March 2017

38 A nuclide of element X undergoes β-decay. Which statement is correct? A The nucleon number increases by 1. B The nucleon number stays the same. C The product is another nuclide of an isotope of X. D The proton number decreases by 1.

1 marks

Answer: B

This question in 0625/21 May/June 2017

39 A sample of radioactive isotope is decaying. The nuclei of which atoms will decay first? A It is impossible to know because radioactive decay is random. B It is impossible to know unless the age of the material is known. C The atoms near the centre will decay first because they are surrounded by more atoms. D The atoms near the surface will decay first because the radiation can escape more easily.

1 marks

Answer: A

This question in 0625/21 May/June 2017

40 A detector of ionising radiation gives a background reading of 20 counts / minute. A radioactive isotope with a half-life of 2.0 days is brought near to the detector. The reading on the detector increases to 100 counts / minute. How long does it take for the reading on the detector to decrease to 40 counts / minute? A 2.0 days B 4.0 days C 5.0 days D 10 days

1 marks

Answer: B

This question in 0625/21 May/June 2017

39 A sample of radioactive isotope is decaying. The nuclei of which atoms will decay first? A It is impossible to know because radioactive decay is random. B It is impossible to know unless the age of the material is known. C The atoms near the centre will decay first because they are surrounded by more atoms. D The atoms near the surface will decay first because the radiation can escape more easily.

1 marks

Answer: A

This question in 0625/22 May/June 2017

40 A sample of a radioactive isotope emits particles at a rate of 240 per minute. After 48 hours the rate of emission has decreased to 15 per minute. What is the half-life of the radioactive material? A 4.0 hours B 8.0 hours C 12 hours D 16 hours

1 marks

Answer: C

This question in 0625/22 May/June 2017

37 When a source of D-particles is directed towards a thin metal foil they become scattered. Which observation of this experiment provides evidence for a small charged nucleus? A A small proportion of the D-particles come straight back from the foil towards the source. B A small proportion of the D-particles pass straight through the foil. C Some of the D-particles are deflected by an angle of less than 90°. D Some of the D-particles follow a curved path after leaving the foil.

1 marks

Answer: A

This question in 0625/23 May/June 2017

39 A sample of radioactive isotope is decaying. The nuclei of which atoms will decay first? A It is impossible to know because radioactive decay is random. B It is impossible to know unless the age of the material is known. C The atoms near the centre will decay first because they are surrounded by more atoms. D The atoms near the surface will decay first because the radiation can escape more easily.

1 marks

Answer: A

This question in 0625/23 May/June 2017

40 A student determines the half-life of a radioactive isotope. The student uses a detector over five minutes and plots a graph showing how the count rate shown on the detector varies with time. The count rate due to background radiation is 30 counts per minute. 250 count rate counts / minute 200 150 100 50 0 0 1 2 3 4 5 time / minutes What is the half-life of this isotope? A 0.30 minutes B 1.2 minutes C 1.5 minutes D 5.0 minutes

1 marks

Answer: B

This question in 0625/23 May/June 2017

38 Emissions X and Y from radioactive material are passed through a magnetic field. The diagram shows the direction of the emissions, the direction of the magnetic field and the effect on the emissions. emission X magnetic field emission Y into the page Which type of emission is X, and which type of emission is Y? emission X emission Y A α-particles β-particles B α-particles γ-rays C β-particles α-particles D β-particles γ-rays

1 marks

Answer: A

This question in 0625/21 Oct/Nov 2017

39 What is meant by the half-life of a radioactive isotope? A half of the time taken for all of the original nuclei to decay B the time taken for half of the original nuclei to decay C the time taken for the charges on all the nuclei to halve D the time taken for the mass of each nucleus to halve

1 marks

Answer: B

This question in 0625/21 Oct/Nov 2017

40 The rate of emission of a radioactive source is measured until the reading reaches the background rate of 20 counts per minute. The results are shown. 200 190 180 rate of emission 170 counts / minute 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0 0 10 20 30 40 50 60 time / minute What is the best estimate of the half-life of the source? A 10 minutes B 12 minutes C 14 minutes D 30 minutes

1 marks

Answer: A

This question in 0625/21 Oct/Nov 2017

38 In the diagram, the circle represents an atom (not to scale) with the nucleus at its centre. A particle is emitted by a radioactive source and approaches the nucleus of the atom. The curved arrow shows the path of the particle. nucleus path of particle What is the nature and charge of the particle? nature of particle charge of particle A α-particle negative B α-particle positive C β-particle negative D β-particle positive

1 marks

Answer: B

This question in 0625/22 Oct/Nov 2017

39 Which row describes the behaviour of γ-rays in an electric field and in a magnetic field? electric field magnetic field A deflected deflected B deflected undeflected C undeflected deflected D undeflected undeflected

1 marks

Answer: D

This question in 0625/22 Oct/Nov 2017

40 A radioactive source has a half-life of 0.5 hours. A detector near the source shows a reading of 6000 counts per second. Background radiation can be ignored. What is the reading on the detector 1.5 hours later? A 750 counts per second B 1500 counts per second C 2000 counts per second D 3000 counts per second

1 marks

Answer: A

This question in 0625/22 Oct/Nov 2017

38 Radioactive carbon-14 decays to nitrogen-14 by the emission of a particle. 14 C → 14 N + particle 6 7 Which particle has been emitted in this process? A a β-particle B an α-particle C a neutron D a proton

1 marks

Answer: A

This question in 0625/23 Oct/Nov 2017

39 As α-particles pass through the electric field between two charged plates, they are deflected downwards. + + + + + + + + + α-particles – – – – – – – – – What happens to γ-rays passing through the same electric field? A They are deflected downwards more than the α-particles. B They are deflected upwards. C They are not deflected at all. D They follow the same path as the α-particles.

1 marks

Answer: C

This question in 0625/23 Oct/Nov 2017

40 Radioactive iodine-131 emits β-particles and has a half-life of 8 days. It decays to produce xenon-131. Which statement about this decay is correct? A After 8 days no more β-particles are emitted. B After 8 days the number of xenon-131 atoms has halved. C After 16 days the iodine-131 has decayed completely. D After 16 days the number of iodine-131 atoms has reduced to one quarter.

1 marks

Answer: D

This question in 0625/23 Oct/Nov 2017

39 The diagram shows emissions from a source passing into the electric field between two charged plates. + + + + + + + + + + source – – – – – – – – – – What is emitted by this source? A neutrons and γ-rays only B α-particles and β-particles only C α-particles and γ-rays only D β-particles and γ-rays only

1 marks

Answer: C

This question in 0625/21 May/June 2018

40 The graph shows how the count rate registered by a counter near to a sample of a radioactive isotope changes over a period of a few days. The background count rate is 5 counts per minute. 50 count rate 40 counts / minute 30 20 10 0 0 1 2 3 4 5 6 7 8 time / days What is the half-life of the isotope? A 2.0 days B 2.5 days C 3.0 days D 4.0 days

1 marks

Answer: A

This question in 0625/21 May/June 2018

38 An isotope of polonium has the nuclide notation 218 Po . 84 A nucleus of this isotope decays by emitting an α-particle. A β-particle is then emitted to form nuclide X. What is the notation for nuclide X? A 214 81X B 213 82 X C 213 83 X D 214 83 X

1 marks

Answer: D

This question in 0625/22 May/June 2018

39 The table compares the penetrating abilities and ionising effects of α-radiation and of γ-radiation. Which row is correct? least most penetrating ionising A α α B α γ C γ α D γ γ

1 marks

Answer: A

This question in 0625/22 May/June 2018

40 The graph shows how the count rate registered by a counter near to a sample of a radioactive isotope changes over a period of a few days. The background count rate is 5 counts per minute. 50 count rate 40 counts / minute 30 20 10 0 0 1 2 3 4 5 6 7 8 time / days What is the half-life of the isotope? A 2.0 days B 2.5 days C 3.0 days D 4.0 days

1 marks

Answer: A

This question in 0625/22 May/June 2018

38 The radiation from a radioactive source passes between two metal plates, and is deflected as shown in the diagram. Between the plates there is a magnetic field directed into the plane of the paper, as indicated by the crosses. × × × × × × × × × × × × × × × × × × × × Only one type of radiation is present. Which situation is possible? A The source emits alpha particles and there is an upwards electric field between the plates. B The source emits alpha particles and there is no electric field between the plates. C The source emits beta particles and there is an upwards electric field between the plates. D The source emits gamma radiation and there is a downwards electric field between the plates.

1 marks

Answer: C

This question in 0625/23 May/June 2018

39 The nucleus of an isotope of nitrogen (N) absorbs a neutron. It then decays into an isotope of carbon (C) and emits x. 1 0 + n 14 N → 14 C + x 7 6 What is x? A α-particle B β-particle C γ-radiation D proton

1 marks

Answer: D

This question in 0625/23 May/June 2018

40 The graph shows how the count rate registered by a counter near to a sample of a radioactive isotope changes over a period of a few days. The background count rate is 5 counts per minute. 50 count rate 40 counts / minute 30 20 10 0 0 1 2 3 4 5 6 7 8 time / days What is the half-life of the isotope? A 2.0 days B 2.5 days C 3.0 days D 4.0 days

1 marks

Answer: A

This question in 0625/23 May/June 2018

38 When a uranium-235 nucleus absorbs a neutron, it becomes unstable and undergoes fission. The fission process produces a barium (Ba) nucleus, a krypton (Kr) nucleus and 3 neutrons. The fission process is represented by the nuclear equation shown. 1 n + 235 U → 144 Ba + Kr ... + 3 n 1 0 92 56 ... 0 Which symbol represents the resulting krypton nucleus? A 89 Kr B 91 Kr C 91 Kr D 91 Kr 36 34 35 36

1 marks

Answer: A

This question in 0625/21 Oct/Nov 2018

39 The diagram shows the paths of three different types of radiation X, Y and Z. X Y Z 2 mm of 10 mm of 50 mm plastic aluminium of lead Which row correctly identifies X, Y and Z? X Y Z A α-particles β-particles γ-rays B β-particles α-particles γ-rays C β-particles γ-rays α-particles D γ-rays α-particles β-particles

1 marks

Answer: B

This question in 0625/21 Oct/Nov 2018

40 A scientist measures the count rate of a radioactive sample in a laboratory over a period of 12 weeks. The background radiation count rate in the laboratory remains constant at 20 counts per minute. The table shows the scientist’s results before the background radiation count rate is taken into account. time count rate / weeks / counts per minute 0 100 2 80 4 65 6 54 8 45 10 39 12 34 In which range does the half-life of the radioactive isotope lie? A between 4 and 6 weeks B between 6 and 8 weeks C between 8 and 10 weeks D more than 12 weeks

1 marks

Answer: A

This question in 0625/21 Oct/Nov 2018

38 A radioactive nucleus 220 Rn decays in two stages to produce 212 Pb . 86 82 Which two particles are emitted in this process? A an α-particle and a β-particle B an α-particle and a proton C two α-particles D two β-particles

1 marks

Answer: C

This question in 0625/22 Oct/Nov 2018

39 The diagram shows the paths of three different types of radiation X, Y and Z. X Y Z 2 mm of 10 mm of 50 mm plastic aluminium of lead Which row correctly identifies X, Y and Z? X Y Z A α-particles β-particles γ-rays B β-particles α-particles γ-rays C β-particles γ-rays α-particles D γ-rays α-particles β-particles

1 marks

Answer: B

This question in 0625/22 Oct/Nov 2018

40 The count rate measured when near a radioactive source drops from 542 counts per minute to 94 counts per minute in 12 hours. The background count remains constant at 30 counts per minute. What is the half-life of the source? A 2 hours B 3 hours C 4 hours D 8 hours

1 marks

Answer: C

This question in 0625/22 Oct/Nov 2018

38 A nucleus of 228 Ra decays into an isotope of actinium, which then decays into a nucleus of 88 228 Th . 90 What types of radiation have been emitted during this process? A one alpha particle only B one alpha particle and one beta particle C two alpha particles D two beta particles

1 marks

Answer: D

This question in 0625/23 Oct/Nov 2018

39 The diagram shows the paths of three different types of radiation X, Y and Z. X Y Z 2 mm of 10 mm of 50 mm plastic aluminium of lead Which row correctly identifies X, Y and Z? X Y Z A α-particles β-particles γ-rays B β-particles α-particles γ-rays C β-particles γ-rays α-particles D γ-rays α-particles β-particles

1 marks

Answer: B

This question in 0625/23 Oct/Nov 2018

40 The count rate due to a sample of a radioactive isotope is measured for 80 minutes. time count rate / minutes counts / second 0 480 20 380 40 300 60 240 80 190 What is the half-life of the isotope? A 20 minutes B 40 minutes C 60 minutes D 80 minutes

1 marks

Answer: C

This question in 0625/23 Oct/Nov 2018

39 A radioactive isotope of carbon 14C decays by beta emission to give an isotope of nitrogen 14N and a beta particle. The equation for the reaction is shown. 14C → 14N + 0β X 7 Y What is the value of X and of Y? X Y A 6 –1 B 6 1 C 8 –1 D 8 1

1 marks

Answer: A

This question in 0625/22 Feb/March 2019

40 A beta particle is a fast moving electron. Which statement explains how beta particles are emitted from an atom? A An electron is emitted as a beta particle from an inner electron shell of the atom. B An electron is emitted as a beta particle from an outer electron shell of the atom. C A neutron changes into a proton and a beta particle is emitted from the nucleus. D A proton changes into a neutron and a beta particle is emitted from the nucleus.

1 marks

Answer: C

This question in 0625/22 Feb/March 2019

38 The chemical symbol for sodium is Na. The equation represents the radioactive decay of sodium-24. 24Na → 24Mg + ye 11 x –1 What are the numbers x and y? x y A 10 0 B 10 1 C 12 0 D 12 1

1 marks

Answer: C

This question in 0625/21 May/June 2019

39 A radioactive source emits α-particles, β-particles and γ-rays into a vacuum where there is a magnetic field. The magnetic field acts perpendicularly into the plane of the paper. The paths X, Y and Z of the three types of radiation through the magnetic field are shown. Y X magnetic field into paper Z radioactive source Which radiation follows path X, path Y and path Z? X Y Z A α-particles β-particles γ-rays B α-particles γ-rays β-particles C β-particles α-particles γ-rays D β-particles γ-rays α-particles

1 marks

Answer: B

This question in 0625/21 May/June 2019

40 A student measures the level of radiation emitted from a radioactive substance. He places a detector very close to the substance. He puts different absorbers between the radioactive substance and the detector. radioactive substance counter detector absorber The student’s results are shown. These results are corrected for background radiation. counter reading absorber counts per minute none 95 thin paper 52 few mm of aluminium 52 several cm of lead 12 Which types of radiation are being emitted by the substance? A α-particles and β-particles only B α-particles and γ-rays only C β-particles and γ-rays only D α-particles, β-particles and γ-rays

1 marks

Answer: B

This question in 0625/21 May/June 2019

38 Which observation provides evidence for the nuclear atom? A attraction of opposite charges B emission of γ-rays during the decay of a radioactive nuclide C scattering of α-particles by thin metal foils D scattering of γ-rays by a thin metal foil

1 marks

Answer: C

This question in 0625/22 May/June 2019

39 The chemical symbol for uranium is U. The equation represents the radioactive decay of uranium-235. 235U → xTh + 4He 92 y 2 What are the numbers x and y? x y A 231 94 B 231 90 C 239 94 D 239 90

1 marks

Answer: B

This question in 0625/22 May/June 2019

40 An experiment is done to measure the radiation from a radioactive source that has a half-life of 10 minutes. The source is placed close to a detector that is connected to a counter, as shown. radioactive counter detector source The average background count-rate is 20 counts / minute. At the start of the experiment, the count-rate recorded by the counter is 1000 counts / minute. What is the count-rate 10 minutes later? A 490 counts / minute B 500 counts / minute C 510 counts / minute D 530 counts / minute

1 marks

Answer: C

This question in 0625/22 May/June 2019

36 α-particles are directed at a metal foil. Most of the particles pass through the foil with little change in direction. A small proportion of the particles are scattered back through large angles. What does this evidence suggest about the structure of an atom? A It consists of a charged centre much smaller than the size of the atom and with little of the mass of the atom. B It consists of a negative charge the size of the atom containing small positive charges scattered through it. C It consists of a charged centre much smaller than the size of the atom but with most of the mass of the atom. D It consists of a positive charge the size of the atom containing small negative charges scattered through it.

1 marks

Answer: C

This question in 0625/23 May/June 2019

39 Which statement about γ-radiation is correct? A It consists of very small charged particles. B It is a form of electromagnetic radiation. C It is less penetrating than β-radiation. D It is more highly ionising than α-radiation.

1 marks

Answer: B

This question in 0625/23 May/June 2019

40 A radium nucleus with nucleon number 226 decays by emitting an α-particle. The proton number of radium is 88. What are the nucleon number and proton number for the nucleus produced by this decay? nucleon number proton number A 222 86 B 222 87 C 226 86 D 226 87

1 marks

Answer: A

This question in 0625/23 May/June 2019

38 The scattering of particles by a thin gold foil provided scientists with evidence for the nuclear atom. Which particles were scattered by the gold nuclei in the thin foil? A α-particles B β-particles C neutrons D protons

1 marks

Answer: A

This question in 0625/21 Oct/Nov 2019

39 The diagram shows β-particles being directed between the poles of a magnet. N β-particles S In which direction will the particles be deflected? A into the page B out of the page C towards the bottom of the page D towards the top of the page

1 marks

Answer: B

This question in 0625/21 Oct/Nov 2019

40 Why are some radioactive sources stored in boxes made from lead? A Lead absorbs emissions from the radioactive sources. B Lead decreases the half-life of radioactive sources. C Lead increases the half-life of radioactive sources. D Lead repels emissions from the radioactive sources.

1 marks

Answer: A

This question in 0625/21 Oct/Nov 2019

38 Plutonium-238 decays by the emission of an α-particle. Which equation represents the decay of a plutonium-238 nucleus? 238 94Pu → 238 95U + 0 –1α A 238 94Pu → 234 92U + 4 2α B 238 94Pu → 234 92U + 2 4α C 238 94Pu → 242 96U + 4 2α D

1 marks

Answer: B

This question in 0625/22 Oct/Nov 2019

39 A radioactive isotope has a half-life of 8 days. A detector close to a sample of this isotope gives a count rate of 200 counts per minute. Without the source, the background count is 20 counts per minute. What is the count rate due to the source after 8 days? A 80 counts per minute B 90 counts per minute C 100 counts per minute D 110 counts per minute

1 marks

Answer: B

This question in 0625/22 Oct/Nov 2019

40 Why are some radioactive sources stored in boxes made from lead? A Lead absorbs emissions from the radioactive sources. B Lead decreases the half-life of radioactive sources. C Lead increases the half-life of radioactive sources. D Lead repels emissions from the radioactive sources.

1 marks

Answer: A

This question in 0625/22 Oct/Nov 2019

37 Why are some radioactive sources stored in boxes made from lead? A Lead absorbs emissions from the radioactive sources. B Lead decreases the half-life of radioactive sources. C Lead increases the half-life of radioactive sources. D Lead repels emissions from the radioactive sources.

1 marks

Answer: A

This question in 0625/23 Oct/Nov 2019

39 A thin metal foil is placed in a vacuum. α-particles are fired at the foil and most go straight through. A very small proportion of the α-particles are deflected through large angles. What does this provide evidence for? A α-particles are very small. B There are negative electrons in each atom. C There is a tiny nucleus in each atom. D There are neutrons in each atom.

1 marks

Answer: C

This question in 0625/23 Oct/Nov 2019

40 The background count rate measured by a radiation counter is 40 counts per minute. With the counter close to a radioactive source, the counter reading is 960 counts per minute. The half-life of the source is 20 minutes. What is the counter reading one hour later? A 115 counts per minute B 120 counts per minute C 155 counts per minute D 160 counts per minute

1 marks

Answer: C

This question in 0625/23 Oct/Nov 2019

38 When Rutherford bombarded thin gold foil with α-particles, he found that some α-particles were deflected through large angles. Which statement explains this deflection? A Most of the atom consists of empty space. B All of the positive charge and most of the mass of the gold atom are concentrated in a small volume. C Positive charge in the gold atom is spread evenly throughout the atom. D All of the negative charge is concentrated at its centre.

1 marks

Answer: B

This question in 0625/22 Feb/March 2020

39 The diagram shows the path followed by α-particles as they pass between two charged plates. They are deflected downwards. + + + + + + + + + β-particles α-particles – – – – – – – – – What happens to β-particles passing through the same electric field? A They are deflected downwards more than the α-particles. B They are deflected upwards. C They are not deflected at all. D They are deflected downwards by the same amount as the α-particles.

1 marks

Answer: B

This question in 0625/22 Feb/March 2020

40 The graph shows the count rate from a radioactive source over a period of time. 2000 count rate counts / s 1500 1000 500 0 0 1 2 3 time / hours What is the half-life of the source? A 0.5 hour B 1.0 hour C 1.5 hours D 3.0 hours

1 marks

Answer: B

This question in 0625/22 Feb/March 2020

37 Uranium-235 is a radioactive isotope. It undergoes a chain of decays and eventually forms the stable isotope lead-207. These two isotopes are represented as shown. 235U 207Pb 92 82 During this chain of decay, how many protons and how many neutrons are lost from a single nucleus of uranium-235 to form a single nucleus of lead-207? protons neutrons A 10 18 B 10 28 C 18 10 D 28 10

1 marks

Answer: A

This question in 0625/21 May/June 2020

38 A radioactive material has a half-life of 20 days. A sample of the material contains 8.0 × 1010 atoms. How many atomic nuclei have decayed after 60 days? A 1.0 × 1010 B 4.0 × 1010 C 6.0 × 1010 D 7.0 × 1010

1 marks

Answer: D

This question in 0625/21 May/June 2020

39 A thin sheet of paper is placed between a radioactive source and a radiation detector. The count rate falls to a very low reading. paper detector counter source From this result, which type of radiation is the source emitting? A α-particles B β-particles C γ-rays D X-rays

1 marks

Answer: A

This question in 0625/21 May/June 2020

40 α-particles, β-particles and γ-rays are emitted by radioactive nuclei when they decay. Which emissions can be deflected by an electric field? A α-particles and β-particles only B β-particles and γ-rays only C γ-rays and α-particles only D α-particles, β-particles and γ-rays

1 marks

Answer: A

This question in 0625/21 May/June 2020

38 A radioactive material has a half-life of 20 days. A sample of the material contains 8.0 × 1010 atoms. How many atomic nuclei have decayed after 60 days? A 1.0 × 1010 B 4.0 × 1010 C 6.0 × 1010 D 7.0 × 1010

1 marks

Answer: D

This question in 0625/22 May/June 2020

39 A thin sheet of paper is placed between a radioactive source and a radiation detector. The count rate falls to a very low reading. paper detector counter source From this result, which type of radiation is the source emitting? A α-particles B β-particles C γ-rays D X-rays

1 marks

Answer: A

This question in 0625/22 May/June 2020

40 α-particles, β-particles and γ-rays are emitted by radioactive nuclei when they decay. Which emissions can be deflected by an electric field? A α-particles and β-particles only B β-particles and γ-rays only C γ-rays and α-particles only D α-particles, β-particles and γ-rays

1 marks

Answer: A

This question in 0625/22 May/June 2020

37 What occurs during nuclear fusion? A Two light atomic nuclei join together and emit energy. B Two light atomic nuclei join together and absorb energy. C A heavy atomic nucleus splits and emits energy. D A heavy atomic nucleus splits and absorbs energy.

1 marks

Answer: A

This question in 0625/23 May/June 2020

38 A radioactive material has a half-life of 20 days. A sample of the material contains 8.0 × 1010 atoms. How many atomic nuclei have decayed after 60 days? A 1.0 × 1010 B 4.0 × 1010 C 6.0 × 1010 D 7.0 × 1010

1 marks

Answer: D

This question in 0625/23 May/June 2020

39 A thin sheet of paper is placed between a radioactive source and a radiation detector. The count rate falls to a very low reading. paper detector counter source From this result, which type of radiation is the source emitting? A α-particles B β-particles C γ-rays D X-rays

1 marks

Answer: A

This question in 0625/23 May/June 2020

40 α-particles, β-particles and γ-rays are emitted by radioactive nuclei when they decay. Which emissions can be deflected by an electric field? A α-particles and β-particles only B β-particles and γ-rays only C γ-rays and α-particles only D α-particles, β-particles and γ-rays

1 marks

Answer: A

This question in 0625/23 May/June 2020

37 A beam of particles moves through a magnetic field. In which situation do the particles experience a magnetic force? A a beam of -particles moving parallel to the magnetic field lines B a beam of electrons moving parallel to the magnetic field lines C a beam of -particles moving perpendicularly across the magnetic field lines D a beam of neutrons moving perpendicularly across the magnetic field lines

1 marks

Answer: C

This question in 0625/21 Oct/Nov 2020

39 Two beams of radiation, P and Q, enter an electric field as shown. + + + + + + + + P Q – – – – – – – – Which type of radiations are P and Q? P Q A beta () alpha () B beta () gamma () C gamma () alpha () D gamma () gamma ()

1 marks

Answer: A

This question in 0625/21 Oct/Nov 2020

40 Which equation represents the B-decay of lead-209? A B “ePb + Se > “3,8 “ePb + Je 5 Tl “aePb > “3,Bi + Je oe 2P b > onl 1 + Je

1 marks

Answer: C

This question in 0625/21 Oct/Nov 2020

39 The diagram shows a beam of -particles passing through a strong electric field. + β-particles – In which direction will the -particles be deflected? A upwards towards the top of the page B downwards towards the bottom of the page C into the plane of the page D out of the plane of the page

1 marks

Answer: A

This question in 0625/22 Oct/Nov 2020

40 Which equation represents the B-decay of lead-209? A B “ePb + je > 73,8 “32D + je > “9, Tl aePb > “3,Bi + Je oe 2P b > oT 1 + Je

1 marks

Answer: C

This question in 0625/22 Oct/Nov 2020

39 Which statement about -rays is correct? A They are deflected by both electric and magnetic fields. B They are deflected by magnetic fields but not by electric fields. C They are deflected by electric fields but not by magnetic fields. D They are not deflected either by electric fields or by magnetic fields.

1 marks

Answer: D

This question in 0625/23 Oct/Nov 2020

40 Which equation represents the B-decay of lead-209? A B “ePb + je > 73,8 “32D + je > “9, Tl aePb > “3,Bi + Je oe 2P b > oT 1 + Je

1 marks

Answer: C

This question in 0625/23 Oct/Nov 2020

39 When alpha particles are incident on a thin metal foil, most of them pass through undeviated. What does this observation reveal about the nature of the atom? A The atom has a dense nucleus. B The atom is mostly empty space. C The atom is very small. D The nucleus of the atom is positively charged.

1 marks

Answer: B

This question in 0625/22 Feb/March 2021

40 A laboratory worker measures the count rate from a radioactive source. He records his results in a table. time count rate minutes counts/s 0 100 1.0 73 2.0 54 3.0 41 4.0 31 The average background radiation in the laboratory is 8 counts per second. What is the half-life of the source? A 1.5 minutes B 2.0 minutes C 3.0 minutes D 4.0 minutes

1 marks

Answer: B

This question in 0625/22 Feb/March 2021

39 Some radioactive nuclei decay to give new nuclei which are also radioactive. Part of a series of decays is shown. 238 92U  234 90Th  234 91Pa  234 92U  230 90Th  226 88Ra How many decays involve the emission of a -particle? A 1 B 2 C 3 D 5

1 marks

Answer: B

This question in 0625/22 May/June 2021

40 The graph shows the activity of a radioactive source over a period of time. 120 activity counts / s 90 60 30 0 0 1 2 3 4 5 time / minutes What is the half-life of the source? A 1.0 minute B 2.0 minutes C 2.5 minutes D 4.0 minutes

1 marks

Answer: B

This question in 0625/22 May/June 2021

37 The nucleus of an americium atom contains 146 neutrons and 95 protons. It decays by emitting an -particle. How many neutrons and how many protons remain in the nucleus when this form of americium decays? number of neutrons number of protons remaining remaining A 142 93 B 142 95 C 144 93 D 144 95

1 marks

Answer: C

This question in 0625/21 Oct/Nov 2021

38 The graph shows how the count rate measured by a radioactivity detector placed near a radioactive sample changed with time. 600 550 count rate counts / min 500 450 400 350 300 250 200 150 100 50 0 0 1 2 3 4 5 6 7 8 9 10 11 time / h Given that the background count rate is 30 counts / min, what is the half-life of this sample? A 3.4 h B 3.6 h C 4.0 h D 5.5 h

1 marks

Answer: A

This question in 0625/21 Oct/Nov 2021

39 A teacher holds a radioactive source near a detector. The reading on the detector is 320 counts / min. The detector is switched on again after the source has been removed and it shows a reading of 20 counts / min. What is the counts / min solely due to the source and why is there a reading on the detector when there is no radioactive source present? counts / min reason for reading due to the source with no source A 300 zero error on detector B 300 background radiation C 340 zero error on detector D 340 background radiation

1 marks

Answer: B

This question in 0625/21 Oct/Nov 2021

40 Which statement is not correct? A -particles are used to detect cracks in metallic structures. B -particles are used in the measurement of the thickness of paper. C -rays may be used to treat cancer patients. D Smoke alarms contain a weak source of -particles.

1 marks

Answer: A

This question in 0625/21 Oct/Nov 2021

37 The nucleus of an americium atom contains 146 neutrons and 95 protons. It decays by emitting an -particle. How many neutrons and how many protons remain in the nucleus when this form of americium decays? number of neutrons number of protons remaining remaining A 142 93 B 142 95 C 144 93 D 144 95

1 marks

Answer: C

This question in 0625/22 Oct/Nov 2021

38 A sample of americium decays and changes into neptunium. The half-life of americium is 432 years. Which fraction of the americium will remain after 1728 years? 1 1 1 A 0 B 16 C 8 D 4

1 marks

Answer: B

This question in 0625/22 Oct/Nov 2021

39 The graph shows the decay curves of four different radioactive isotopes. Which isotope has the largest half-life? A count rate B C D 0 0 time

1 marks

Answer: A

This question in 0625/22 Oct/Nov 2021

40 The diagrams show a-particles and B-particles passing through an electric field. Which diagram shows the correct paths of the a-particles and B-particles?

1 marks

Answer: B

This question in 0625/22 Oct/Nov 2021

37 The nucleus of an americium atom contains 146 neutrons and 95 protons. It decays by emitting an -particle. How many neutrons and how many protons remain in the nucleus when this form of americium decays? number of neutrons number of protons remaining remaining A 142 93 B 142 95 C 144 93 D 144 95

1 marks

Answer: C

This question in 0625/23 Oct/Nov 2021

38 The half-life for lead-202 is 52 500 years. A sample of lead-202 produces 800 counts / s. How long will it take for the count rate to drop to 100 counts / s? A 105 000 years B 157 500 years C 210 000 years D 420 000 years

1 marks

Answer: B

This question in 0625/23 Oct/Nov 2021

39 Oxygen-15 is used in hospitals. The count rate from a detector placed close to a sample of oxygen-15 was recorded over a period of 15 min. The background count rate is 20 counts / min. 200 180 count rate counts / min 160 140 120 100 80 60 40 20 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 time / min What is the half-life of this sample of oxygen-15? A 2.0 min B 2.4 min C 2.8 min D 7.5 min

1 marks

Answer: A

This question in 0625/23 Oct/Nov 2021

40 Of the three types of ionising radiation, ,  and , why does -emission cause the most ionisation? A -particles have the smallest mass. B -particles have the greatest mass. C -particles move with the greatest speed. D -particles travel the greatest distance in matter.

1 marks

Answer: B

This question in 0625/23 Oct/Nov 2021

38 When a beam of -particles is incident on a thin metal foil, most of them follow a path represented by path X in the diagram. A small number of -particles follow a path represented by path Y in the diagram. foil X Y Which row correctly describes a conclusion that can be drawn from each of these observations about the structure of the atom? most follow path X some follow path Y A atom is mostly empty space atom contains something that repels -particles B atom is mostly empty space nucleus contains protons and neutrons C atom is neutral atom contains something that repels -particles D atom is neutral nucleus contains protons and neutrons

1 marks

Answer: A

This question in 0625/22 Feb/March 2022

40 When a radioactive isotope is set up close to a counter, a count rate of 38 000 counts / s is obtained. The table shows the count rate from the isotope over a three-year period. count rate time / years counts / s 0 38 000 1 26 000 2 17 000 3 12 000 What is the half-life of the isotope? A less than 1 year B more than 1 year but less than 2 years C more than 2 years but less than 3 years D more than 3 years

1 marks

Answer: B

This question in 0625/22 Feb/March 2022

39 Which statement about the radioactive decay of a substance is correct? A It cannot be predicted when a particular nucleus will decay. B Placing a radioactive substance inside a lead-lined box prevents it from decaying. C The decay always produces poisonous gases. D The rate of decay increases if the substance is dissolved in water.

1 marks

Answer: A

This question in 0625/21 May/June 2022

40 The diagram shows a stream of B-particles travelling in a line that passes between the poles of a magnet. Oo B-particles In which direction will the B-particles be deflected by the magnet? A __ towards the N pole B_ towards the S pole C into the page D out of the page

1 marks

Answer: D

This question in 0625/21 May/June 2022

39 Which radioactive source is used in a smoke alarm system and what is the reason for this? source reason A α causes least ionisation of air B α causes most ionisation of air C γ causes least ionisation of air D γ causes most ionisation of air

1 marks

Answer: B

This question in 0625/22 May/June 2022

40 A beam of α-particles and β-particles is incident at right angles to an electric field. Which statement about the deflection of the particles in the field is correct? A α-particles deflect, but β-particles do not deflect. B α-particles deflect in the opposite direction to β-particles. C β-particles deflect, but α-particles do not deflect. D Both α-particles and β-particles deflect in the same direction.

1 marks

Answer: B

This question in 0625/22 May/June 2022

38 Carbon-14 has a proton number (Z) of 6 and a nucleon number (A) of 14. Nitrogen-14 has a proton number of 7 and a nucleon number of 14. Carbon-14 emits β-particles to form nitrogen-14. Which nuclide equation describes this process? A 14 C → 14 N + β 0 1 6 7 B 6 C → 7 N + β 1 0 14 14 C 14 C → 14 N + 1 0 β 6 7 − D 6 C → 7 N + −1 β 14 14 0

1 marks

Answer: C

This question in 0625/23 May/June 2022

39 A beam of radiation, containing α-particles, β-particles and γ-rays, passes between two parallel plates. One plate is positively charged and the other is negatively charged. Which radioactive emissions will be attracted towards the positively charged plate? A α-particles only B β-particles only C γ-rays only D α-particles, β-particles and γ-rays

1 marks

Answer: B

This question in 0625/23 May/June 2022

40 A scientist uses a counter to measure the radioactivity of a sample of nitrogen-13. The counter and sample of nitrogen-13 are on a table in a laboratory. The reading on the counter is recorded for a period of 80 min and a graph is drawn using the measurements. 400 count rate counts / min 300 200 100 0 0 10 20 30 40 50 60 70 80 time / min What is the best estimate for the half-life of the sample of nitrogen-13? A 10 min B 12 min C 14 min D 40 min

1 marks

Answer: A

This question in 0625/23 May/June 2022

38 Polonium, Po, has a proton number equal to 84 and a nucleon number equal to 218. Polonium changes into astatine, At, by emitting a -particle. Which equation represents this decay? 84 Po 8 5 At –1  A  + 218 218 0 84 Po –1  8 5 At B +  218 0 218 218 Po 218 At 0  C  + 8 4 85 – 1 218 Po 0  218 At D +  8 4 – 1 85

1 marks

Answer: C

This question in 0625/21 Oct/Nov 2022

39 The graph shows how the count rate from a radioactive isotope changes with time. 60 count rate 50 counts / s 40 30 20 10 0 0 1 2 3 4 5 6 time / s What is the half-life of this isotope? A 2.0 s B 6.0 s C 12 s D 53 s

1 marks

Answer: A

This question in 0625/21 Oct/Nov 2022

40 What is the nature of -emission? A electromagnetic waves B negatively charged particles C positively charged particles D uncharged particles

1 marks

Answer: C

This question in 0625/21 Oct/Nov 2022

37 A thin metal foil is placed in a vacuum. α-particles are fired at the foil and most go straight through. A very small proportion of the α-particles are deflected through large angles. What does this provide evidence for? A α-particles are very small. B There are negative electrons in each atom. C There is a tiny nucleus in each atom. D There are neutrons in each atom. 230 Th

1 marks

Answer: C

This question in 0625/22 Oct/Nov 2022

38 Thorium-230 is represented by the symbol . This isotope is radioactive and decays to 90 radium by emitting α-particles. Which nuclide is produced by this decay? 226 Ra 2 30 Ra 2 30 Ra 2 34 Ra A B C D 88 89 91 92

1 marks

Answer: A

This question in 0625/22 Oct/Nov 2022

39 The diagram shows a piece of apparatus used to determine the nature of the emissions from a radioactive source. The absorbers can be raised out of or lowered into the path of the radiation from the source to the detector. The apparatus is evacuated. different absorbers detector radioactive source vacuum The table gives a set of results for a particular radioactive source. count rate on detector absorber in use (counts per second) none 350 thin paper 350 1.0 mm aluminium 180 1.0 cm lead 23 Which types of radiation are being emitted by the radioactive source? A α-particles and β-particles B α-particles only C β-particles and γ-rays D β-particles only

1 marks

Answer: C

This question in 0625/22 Oct/Nov 2022

40 The graph shows the measured count rate of radiation from a source containing a radioactive isotope. The detector is in a laboratory, with no shielding from background radiation. X count rate Y 0 0 time What is the measured count rate after a time of one half-life? X Y ( X − Y ) ( X + Y ) A B C D 2 2 2 2

1 marks

Answer: D

This question in 0625/22 Oct/Nov 2022

37 A thin metal foil is placed in a vacuum. -particles are fired at the foil and most go straight through. A very small proportion of the -particles are deflected through large angles. What does this provide evidence for? A -particles are very small. B There are negative electrons in each atom. C There is a tiny nucleus in each atom. D There are neutrons in each atom.

1 marks

Answer: C

This question in 0625/23 Oct/Nov 2022

38 The table compares -radiation, -radiation and -radiation. Which row is correct? -radiation -radiation -radiation A more ionising than  or  a proton electromagnetic radiation B less ionising than  or  an electron two protons and two neutrons C more ionising than  or  an electron electromagnetic radiation D less ionising than  or  electromagnetic radiation a proton

1 marks

Answer: C

This question in 0625/23 Oct/Nov 2022

39 A high-voltage power supply is connected to a metal grid and a wire, as shown. radioactive source emitting a-particles metal grid high voltage 5 observed When the radioactive source is placed close to the grid, sparks are observed in the position indicated. Which statement explains why the sparks are formed? A a-particles have a long range. B~ a-particles have no charge. C_ a-particles have no mass. D a-particles are strongly ionising.

1 marks

Answer: D

This question in 0625/23 Oct/Nov 2022

40 A student investigates four different radioactive isotopes. The student places a detector near each radioactive material. The background count rate is 36 counts per minute throughout the investigation. The table shows the detector readings at the start and after 8 hours. Which isotope has a half-life of 4 hours? count rate at the start count rate after 8 hours counts per minute counts per minute A 150 36 B 212 53 C 260 92 D 356 80

1 marks

Answer: C

This question in 0625/23 Oct/Nov 2022

33 The scattering of α-particles by a thin metal foil supports the nuclear model of an atom. Why are α-particles used rather than neutrons? A because they always travel more slowly B because they are heavier C because they are larger in diameter D because they have a positive charge

1 marks

Answer: D

This question in 0625/22 Feb/March 2023

35 A sample of a radioactive isotope has an initial rate of emission of 128 counts per minute and a half-life of 4 days. How long will it take for the rate of emission to fall to 32 counts per minute? A 2 days B 4 days C 8 days D 12 days

1 marks

Answer: C

This question in 0625/22 Feb/March 2023

36 Several scientists are working in a laboratory. The scientists are experimenting with sources which emit ionising radiation. Each scientist is given a list of safety rules. Three of the rules are shown. 1 Keep at least 2 m away from other people. 2 Do not stay longer than 4 hours per day in the laboratory. 3 Stay behind the lead-lined screen. Which safety rules are for protection against the effects of ionising radiation? A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: D

This question in 0625/22 Feb/March 2023

35 A radioactive source is placed near a detector connected to a counter. 210 counts are recorded by the counter in 3 minutes. The background count rate is 20 counts per minute (cpm). What is the corrected count rate for the radioactive source? A 50 cpm B 70 cpm C 190 cpm D 270 cpm

1 marks

Answer: A

This question in 0625/21 May/June 2023

36 The background count rate measured by a radiation counter is 40 counts per minute (cpm). With the counter close to a radioactive source, the counter reading is 960 cpm. The half-life of the source is 20 minutes. What is the counter reading one hour later? A 115 cpm B 120 cpm C 155 cpm D 160 cpm

1 marks

Answer: C

This question in 0625/21 May/June 2023

35 Which change occurs in the nucleus of a radioactive atom during β-emission? A A neutron transforms into a proton and an electron. B A neutron transforms into a proton only. C A proton transforms into a neutron and an electron. D A proton transforms into a neutron only.

1 marks

Answer: A

This question in 0625/22 May/June 2023

36 A radioactive isotope has a half-life of 8 days. A detector close to a sample of this isotope gives a count rate of 200 counts per minute. Without the source, the background count is 20 counts per minute. What is the count rate due to the source after 8 days? A 80 counts per minute B 90 counts per minute C 100 counts per minute D 110 counts per minute

1 marks

Answer: B

This question in 0625/22 May/June 2023

35 Which change is occurring in a nucleus during -emission? A An electron and a neutron become one proton. B An electron and a proton become one neutron. C A neutron becomes one proton and one electron. D A proton becomes one neutron and one electron.

1 marks

Answer: C

This question in 0625/23 May/June 2023

36 The graph shows how the count rate registered by a counter near to a sample of a radioactive isotope changes over a period of a few days. The background count rate is 5 counts per minute. 50 count rate 40 counts / minute 30 20 10 0 0 1 2 3 4 5 6 7 8 time / days What is the half-life of the isotope? A 2.0 days B 2.5 days C 3.0 days D 4.0 days

1 marks

Answer: A

This question in 0625/23 May/June 2023

35 -particles, -particles and -rays are emitted by radioactive nuclei when they decay. Which emissions can be deflected by an electric field? A -particles, -particles and -rays B -particles and -particles only C -particles and -rays only D -rays and -particles only

1 marks

Answer: B

This question in 0625/21 Oct/Nov 2023

36 Radioisotope X decays to the stable isotope Y. The graph shows how the mass of Y present in a sample varies with time. M mass of Y M 2 M 4 0 0 t1 t2 t3 time Which time interval gives the half-life of X? A t2 – t1 B t3 – t2 C t2 D 2 t3 1

1 marks

Answer: C

This question in 0625/21 Oct/Nov 2023

35 Which row correctly describes an example of radioactive decay? original change or emission nucleus no change of element A stable  change of element B unstable  change of element C unstable  no change of element D unstable  no change of element

1 marks

Answer: B

This question in 0625/22 Oct/Nov 2023

36 A radioactive isotope of sodium has a half-life of 15 h. The table gives data from an experiment to show how the rate of decay of the isotope varies with time. The background count rate has not been subtracted from these data. time / h 0 10 20 30 count rate 400 260 170 115 counts / s What is the background radiation count rate? A 12 counts / s B 15 counts / s C 20 counts / s D 30 counts / s

1 marks

Answer: C

This question in 0625/22 Oct/Nov 2023

34 The scattering of a-particles by a thin gold foil provides evidence for the nuclear model of the atom. Two a-particles of the same energy are incident on a nucleus of gold. Which diagram shows the correct paths followed by the a-particles as they pass close to the nucleus? A B path of a-particle @ gold nucleus Cc D @ @

1 marks

Answer: A

This question in 0625/23 Oct/Nov 2023

35 The half-life of carbon-14 is 5700 years. An object containing carbon-14 has a count rate of 100 counts / minute when it is first formed. The graph shows how the count rate decreases over time. Which point on the graph corresponds to a time 11 400 years after the formation of the object? 100 count rate A counts / minute B C D 0 0 time

1 marks

Answer: D

This question in 0625/23 Oct/Nov 2023

36 Why are beta-particles deflected more strongly than alpha-particles when they enter an electric field? A Beta-particles have less mass than alpha-particles. B Beta-particles are negatively charged. C Beta-particles have lower velocities than alpha-particles. D Beta-particles have more ionising power than alpha-particles.

1 marks

Answer: A

This question in 0625/23 Oct/Nov 2023

31 A student is investigating the count rate of a radioactive substance. How must he adjust his reading for the background count? A Add the background count to his reading. B Ignore the background count as it will not affect his reading. C Subtract the background count from his reading. D Take repeat readings to eliminate the background count.

1 marks

Answer: C

This question in 0625/22 Feb/March 2024

34 The radioactive isotope radon, 222 Rn, is an alpha () emitter. 86 During this radioactive decay, an isotope of polonium, Po, is produced. How many neutrons does a nucleus of this isotope of polonium contain? A 130 B 132 C 134 D 136

1 marks

Answer: C

This question in 0625/22 Feb/March 2024

35 Which statement gives two safety precautions to take when a person is working with ionising radiation? A decrease exposure time and decrease distance between the person and the source B decrease exposure time and increase distance between the person and the source C increase exposure time and decrease distance between the person and the source D increase exposure time and increase distance between the person and the source

1 marks

Answer: B

This question in 0625/22 Feb/March 2024

35 A radioactive source is placed near a detector. The radiation arriving at the detector from the source is measured for 10 minutes with different materials placed between the source and the detector. materials placed here radioactive detector source material between radiation detected source and detector / counts none 5626 sheet of paper 5629 thick sheet of aluminium 2226 thick sheet of lead 255 Which types of radiation are emitted by the source? A -particles and -rays B -particles only C -particles and -rays D -particles only

1 marks

Answer: C

This question in 0625/21 May/June 2024

36 The reading on a detector placed near a radioactive material is 536 counts per second. The background count rate is 44 counts per second. The half-life of the radioactive material is 34 hours. What is the reading on the detector after 68 hours? A 44 counts per second B 123 counts per second C 134 counts per second D 167 counts per second

1 marks

Answer: D

This question in 0625/21 May/June 2024

33 The scattering of particles by a thin gold foil provided scientists with evidence for the nuclear atom. Which particles were scattered by the gold nuclei in the thin foil? A -particles B -particles C neutrons D protons

1 marks

Answer: A

This question in 0625/22 May/June 2024

35 The dashed line on the graph shows the decay curve recorded from a sample of a particular radioactive isotope. The count rate includes background radiation. 80 count rate 70 counts / minute 60 50 40 30 20 10 0 0 1 2 3 4 5 6 7 8 9 10 time / days Which curve shows the corrected count rate for the decay? A B 80 80 corrected 70 corrected 70 count rate 60 count rate 60 counts / minute 50 counts / minute 50 40 40 30 30 20 20 10 10 0 0 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 time / days time / days C D 80 80 corrected 70 corrected 70 count rate 60 count rate 60 counts / minute 50 counts / minute 50 40 40 30 30 20 20 10 10 0 0 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 time / days time / days

1 marks

Answer: B

This question in 0625/22 May/June 2024

36 Which type of radioactive source is suitable for use in measuring and controlling the thickness of paper in a paper-manufacturing factory? type of emission half-life A alpha long B alpha short C beta long D beta short

1 marks

Answer: C

This question in 0625/22 May/June 2024

37 A medical tracer is used to investigate a tumour in a patient. The graph shows the corrected count rate from the tracer against time. 10 000 corrected count rate 9 000 counts / s 8 000 7 000 6 000 5 000 4 000 3 000 2 000 1 000 0 0 1 2 3 4 5 6 7 8 9 10 time / min What is the half-life of the source? A 2 minutes B 10 minutes C 5 000 minutes D 10 000 minutes

1 marks

Answer: A

This question in 0625/22 May/June 2024

34 What is nuclear fission? A the merging of two nuclei to create a heavier nucleus B the process by which electrons are removed from an atom C the process by which stars generate energy D the splitting of a nucleus to create two smaller nuclei

1 marks

Answer: D

This question in 0625/23 May/June 2024

35 The diagram represents the paths of three types of ionising radiation, X, Y and Z, through a magnetic field. The three types of radiation are alpha, beta and gamma. X magnetic field Y Z Which statement about the ionising radiation is correct? A X is positively charged. B Y is negatively charged. C Z is the most strongly ionising. D X has a smaller mass than Y.

1 marks

Answer: C

This question in 0625/23 May/June 2024

36 Which row correctly matches three radioactive sources to their uses? emits alpha-particles emits beta-particles emits gamma radiation and has a long half-life and has a long half-life and has a short half-life A monitoring the thickness smoke alarm tracer to be injected of aluminium foil to detect cancer B monitoring the thickness tracer to be injected smoke alarm of aluminium foil to detect cancer C smoke alarm monitoring the thickness tracer to be injected of aluminium foil to detect cancer D smoke alarm tracer to be injected monitoring the thickness to detect cancer of aluminium foil

1 marks

Answer: C

This question in 0625/23 May/June 2024

37 Why are some radioactive sources stored in boxes made from lead? A Lead absorbs emissions from the radioactive sources. B Lead decreases the half-life of radioactive sources. C Lead increases the half-life of radioactive sources. D Lead repels all radioactive emissions.

1 marks

Answer: A

This question in 0625/23 May/June 2024

35 Which statement correctly compares the properties of alpha-particles and beta-particles? A Alpha-particles are less penetrating than beta-particles because alpha-particles are less ionising. B Alpha-particles are less penetrating than beta-particles because alpha-particles are more ionising. C Alpha-particles are more penetrating than beta-particles because alpha-particles are less ionising. D Alpha-particles are more penetrating than beta-particles because alpha-particles are more ionising.

1 marks

Answer: B

This question in 0625/21 Oct/Nov 2024

36 Which statement about alpha decay is correct? A The nucleus loses electrons. B The nucleus changes to that of a different element. C The nucleus does not decay until after one half-life. D After two half-lives, alpha decay always stops.

1 marks

Answer: B

This question in 0625/21 Oct/Nov 2024

37 An explosion in a nuclear reactor spreads the isotope caesium-137, 137 Cs, across a large area. 55 After 90.0 years have passed, the quantity of caesium-137 present is 12.5% of its original level. What is the half-life of caesium-137? A 11.3 years B 22.5 years C 30.0 years D 45.0 years

1 marks

Answer: C

This question in 0625/21 Oct/Nov 2024

35 An -particle and a -particle have the same kinetic energy. Why does the -particle have a larger ionising effect than the -particle as it passes through air? A The -particle has a larger charge and a larger velocity so is closer to an air particle for a shorter time. B The -particle has a larger charge and a smaller velocity so is closer to an air particle for a longer time. C The -particle has a smaller charge and a larger velocity so is closer to an air particle for a shorter time. D The -particle has a smaller charge and a smaller velocity so is closer to an air particle for a longer time.

1 marks

Answer: B

This question in 0625/22 Oct/Nov 2024

36 A student is carrying out an experiment to measure the radiation from a radioactive source. He uses a radiation detector and records the total counts in 5-minute intervals. He does this three times with the source present and three times with the source absent. Here are his results. total counts in total counts in 5 minutes 5 minutes with source present with source absent 68 25 73 28 69 22 What is the average corrected count rate for the source? A 5 counts / minute B 9 counts / minute C 25 counts / minute D 45 counts / minute

1 marks

Answer: B

This question in 0625/22 Oct/Nov 2024

37 The count rate measured near a radioactive source drops from 542 counts per minute to 94 counts per minute in 12 hours. The background count remains constant at 30 counts per minute. What is the half-life of the source? A 2 hours B 3 hours C 4 hours D 8 hours

1 marks

Answer: C

This question in 0625/22 Oct/Nov 2024

34 The products of the decay of a nucleus of a radioactive isotope are a nucleus and radiation which is emitted. What is the nature of the products? A a nucleus of an element different from the isotope is formed and both an -particle and -radiation are emitted B a nucleus of an element different from the isotope is formed and just -radiation is emitted C a nucleus of the same element as the isotope is formed and both a -particle and -radiation are emitted D a nucleus of the same element as the isotope is formed and just an -particle is emitted

1 marks

Answer: A

This question in 0625/23 Oct/Nov 2024

35 An atomic nucleus decays by one or more radioactive decay processes. What causes the proton number to decrease by 1? A -decay followed by -decay B -decay only C -decay followed by -decay D -decay only

1 marks

Answer: A

This question in 0625/23 Oct/Nov 2024

36 Which definition of half-life is not correct? A the time it takes for the count rate from a radioactive sample to fall to half its original value B the time it takes for half of the unstable nuclei in a radioactive sample to decay C the time it takes for the mass of radioactive material in a sample to halve D the time it takes for half of the neutrons in a radioactive sample to decay

1 marks

Answer: D

This question in 0625/23 Oct/Nov 2024

37 The diagram shows a system to control the thickness of paper produced by a machine. The graph shows how the count rate at the detector varies with the thickness of the paper. The rollers squeeze the paper when the count rate at the detector drops below 12 counts per second and then stop squeezing when the count rate rises above 13 counts per second. 25 count rate counts/s B-particle source 20 paper as 15 10 roller 5 B-particle detector 0 0.0 05 1.0 15 2.0 paper thickness/mm What is the thickness of the paper coming out of the machine? A_ between 0.40mm and 0.50 mm B_ between 0.50mm and 0.60 mm C between 0.60mm and 0.70mm D between 0.70mm and 0.80 mm

1 marks

Answer: B

This question in 0625/23 Oct/Nov 2024

34 A uranium nucleus 238 U decays to form thorium by emitting an -particle. Thorium decays to 92 protactinium by emitting a -particle. Which row gives the atomic number and mass number of this isotope of protactinium? atomic number mass number A 89 234 B 90 235 C 91 234 D 95 235

1 marks

Answer: C

This question in 0625/22 Feb/March 2025

35 Which row shows what happens when a nucleus decays by emitting a -particle? change in the nucleus particle emitted A a neutron changes to a electron proton and an electron B a neutron changes to a proton proton and an electron C a proton changes to a electron neutron and an electron D a proton changes to a neutron neutron and an electron

1 marks

Answer: A

This question in 0625/22 Feb/March 2025

36 Which precaution does not always reduce a scientist’s exposure when working with sources of ionising radiation? A ensuring the scientist only works with sources of radiation that have long half-lives B increasing the distance between the scientist and the source of radiation C limiting the time for which the scientist handles the source of radiation D placing a lead shield between the scientist and the source of radiation

1 marks

Answer: A

This question in 0625/22 Feb/March 2025

37 A detector is placed near a radioactive isotope and records a count rate of 700 counts / min. The half-life of the isotope is 8 min. The average background count rate is 60 counts / min. What is the count rate measured by the detector after 16 min? A 100 counts / min B 160 counts / min C 175 counts / min D 220 counts / min

1 marks

Answer: D

This question in 0625/22 Feb/March 2025

38 The nucleus of an isotope of nitrogen, N, absorbs a neutron. It then decays into an isotope of carbon, C, and emits x. 1 n + 14 N  14 C + x 0 7 6 What is x? A -particle B -particle C -radiation D proton

1 marks

Answer: D

This question in 0625/22 Feb/March 2025

35 A detector placed near a radioactive isotope gives a measured count rate of 800 counts / minute. The half-life of the isotope is three hours. The background count rate is 32 counts / minute. What is the count rate on the detector after six hours? A 192 counts / minute B 200 counts / minute C 224 counts / minute D 232 counts / minute

1 marks

Answer: C

This question in 0625/21 May/June 2025

36 Sodium-24 is a radioactive isotope that emits beta radiation. Which nuclear equation shows how sodium-24 decays? 4iNa > 42Mg + 5p “Na > 7Ne + $B 24 20 4 1iNa — “oF + 5B 0 fO DW > 24 20 4 iwNa + 473Al + 3B

1 marks

Answer: A

This question in 0625/21 May/June 2025

37 Which safety precautions must be taken when using a source of gamma radiation? 1 Reduce the distance between the source and the person. 2 Reduce the time of exposure to the radiation. 3 Use a suitable shielding material between the source and the person. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: D

This question in 0625/21 May/June 2025

35 A detector near a radioactive source shows a reading of 2000 counts / minute. How is the corrected count rate determined? A by moving the detector closer to the source B by placing an absorber between the detector and the source C by repeating and averaging the measurements D by taking away the background radiation count rate

1 marks

Answer: D

This question in 0625/22 May/June 2025

36 Which statement about alpha, beta and gamma radiation is not correct? A Alpha particles are deflected most in an electric field. B Beta particles are deflected most in a magnetic field. C Gamma radiation is not deflected by a magnetic field. D Gamma radiation is least ionising.

1 marks

Answer: A

This question in 0625/22 May/June 2025

37 A sample of a radioactive material has a half-life of 20 minutes. Which statement is correct? A After 30 minutes, less than half of the material has decayed. B After 40 minutes, all of the radioactive material has decayed. C After 60 minutes, an eighth of the radioactive material remains. D After 120 minutes, a sixth of the radioactive material remains.

1 marks

Answer: C

This question in 0625/22 May/June 2025

33 A beta particle has less mass than an alpha particle, but the speed of a beta particle emitted during radioactive decay is approximately 20 times greater than the speed of an alpha particle. Which statement correctly compares properties of these two particles? A Alpha particles are less penetrating because they have less kinetic energy than beta particles. B Alpha particles are more penetrating because they have less kinetic energy than beta particles. C Alpha particles are less ionising because they have more kinetic energy than beta particles. D Alpha particles are more ionising because they have more kinetic energy than beta particles.

1 marks

Answer: D

This question in 0625/23 May/June 2025

35 Which effect on living things is not caused by ionising radiation? A cancer B cell death C infection D mutation

1 marks

Answer: C

This question in 0625/23 May/June 2025

36 Isotope X is radioactive. Which statement about X must be correct? A A nucleus of X is unstable. B X emits -particles. C X emits -particles. D X emits -radiation.

1 marks

Answer: A

This question in 0625/23 May/June 2025

37 An experiment is done to measure the radiation from a radioactive source. The source has a half-life of 10 minutes. The source is placed close to a detector that is connected to a counter, as shown. radioactive counter detector source The average background count rate is 20 counts / minute. At the start of the experiment, the count rate recorded by the counter is 1000 counts / minute. What is the count rate 10 minutes later? A 490 counts / minute B 500 counts / minute C 510 counts / minute D 530 counts / minute

1 marks

Answer: C

This question in 0625/23 May/June 2025

34 Three statements about alpha () particles and beta () particles are listed. 1 The magnitude of the charge on an -particle is twice the charge on a -particle. 2 The mass of an -particle is large compared with the mass of a -particle. 3 The kinetic energy of an -particle is small compared to the kinetic energy of a -particle. Which statements help to explain the different ionising effects of -particles and -particles? A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: B

This question in 0625/21 Oct/Nov 2025

35 A beta-particle is a fast-moving electron. Which statement explains how beta-particles are emitted from an atom? A An electron is emitted as a beta-particle from an inner electron shell of the atom. B An electron is emitted as a beta-particle from an outer electron shell of the atom. C A neutron changes into a proton and a beta-particle is emitted from the nucleus. D A proton changes into a neutron and a beta-particle is emitted from the nucleus.

1 marks

Answer: C

This question in 0625/21 Oct/Nov 2025

36 Which properties must a radioisotope have for its radiation to make it suitable to kill bacteria in food? half-life type of radiation emitted A less than one minute  only B several hours  only C several hours  only D several thousand years  only

1 marks

Answer: C

This question in 0625/21 Oct/Nov 2025

37 A student tries to predict the effect of exposure time on the radiation dose received from a source of ionising radiation. Radiation dose measures the amount of ionising radiation received by a living organism. Which graph shows the correct trend between the variables? A B radiation radiation dose dose 0 0 0 exposure 0 exposure time time C D radiation radiation dose dose 0 0 0 exposure 0 exposure time time

1 marks

Answer: A

This question in 0625/21 Oct/Nov 2025

34 A teacher writes the nuclide equation for a fusion reaction. 2 x 4 1 What is the missing number X and the missing element Q? X Q A 2 B 2 He Cc 3 H D 3 He

1 marks

Answer: D

This question in 0625/22 Oct/Nov 2025

35 Radon gas is a source of radiation that contributes to background radiation. What does not contribute to background radiation? A electromagnetic rays B food and drink C rocks D seismic waves

1 marks

Answer: D

This question in 0625/22 Oct/Nov 2025

36 Two beams of radiation, P and S, enter an electric field, as shown. + + + + + + + + P S – – – – – – – – Which types of radiation are P and S? P S A beta () alpha () B beta () gamma () C gamma () alpha () D gamma () gamma ()

1 marks

Answer: A

This question in 0625/22 Oct/Nov 2025

37 Which change takes place in the nucleus when it decays by beta () emission? A neutron + electron  proton B neutron  proton + electron C proton + electron  neutron D proton  neutron + electron

1 marks

Answer: B

This question in 0625/22 Oct/Nov 2025

33 Some students set up an experiment to measure the count rate for a radioactive source. First, they measure the radioactive background count rate in the laboratory by taking three measurements. Each measurement is taken over a 10-minute period. The table shows their results. number of counts in 10 minutes first second third measurement measurement measurement 170 164 185 Next, the students measure the counts near the radioactive source. This count rate is measured as 949 counts per minute. What is the corrected count rate for the source? A 932 counts per minute B 776 counts per minute C 430 counts per minute D 78 counts per minute

1 marks

Answer: A

This question in 0625/23 Oct/Nov 2025

34 A radioactive source emits -particles, -particles and -rays into a vacuum where there is a magnetic field. The magnetic field acts perpendicularly into the plane of the paper. The paths J, K and L of the three types of radiation through the magnetic field are shown. K J magnetic field into paper L radioactive source Which radiation follows path J, path K and path L? J K L A -particles -particles -rays B -particles -rays -particles C -particles -particles -rays D -particles -rays -particles

1 marks

Answer: B

This question in 0625/23 Oct/Nov 2025

35 Radioactive decay is a change in an unstable nucleus which may result in emission of alpha-particles or beta-particles. Which statement describes how these emissions happen? A Alpha emission is a spontaneous and random process but beta emission is not. B Alpha emission and beta emission are both spontaneous and random processes. C Beta emission is a spontaneous and random process but alpha emission is not. D Neither alpha emission nor beta emission are spontaneous and random processes.

1 marks

Answer: B

This question in 0625/23 Oct/Nov 2025

36 Which change occurs in the nucleus of a radioactive atom when a beta-particle is emitted? A neutron  alpha-particle B neutron  proton + electron C proton  neutron D proton  neutron + electron

1 marks

Answer: B

This question in 0625/23 Oct/Nov 2025

37 A radioactive source that emits -particles, -particles and -radiation is stored safely in a container. From which material should the container be made? A alumimium B copper C paper D lead

1 marks

Answer: D

This question in 0625/23 Oct/Nov 2025