Radioactivity — Paper 2 · IGCSE Physics (9-1) 0972

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 0972/21 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 0972/21 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 0972/21 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 0972/21 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 0972/21 Oct/Nov 2018

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 0972/21 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 0972/21 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 0972/21 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 0972/22 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 0972/22 May/June 2019

40 An experiment is carried out 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 0972/22 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 0972/21 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 0972/21 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 0972/21 Oct/Nov 2019

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 0972/21 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 0972/21 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 0972/21 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 0972/21 May/June 2020

37 Uranium-235 can undergo nuclear fission in many ways. Which equation correctly shows a possible fission reaction for uranium-235? 1n 235U 141Ba 92Kr 31n A + → + + 0 92 56 36 0 1n 235U 91Sr 144Xe 21n B + → + + 0 92 38 54 0 1n 235U 95Rb 136Cs 31n C + → + + 0 92 37 55 0 1n 235U 87Br 146La 41n D + → + + 0 92 35 57 0

1 marks

Answer: A

This question in 0972/22 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 0972/22 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 0972/22 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 0972/22 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 0972/21 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 0972/21 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 0972/21 Oct/Nov 2020

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 0972/21 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 0972/21 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 0972/21 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 0972/21 Oct/Nov 2021

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 0972/21 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 0972/21 May/June 2022

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

1 marks

Answer: B

This question in 0972/22 May/June 2022

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

1 marks

Answer: B

This question in 0972/22 May/June 2022

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 0972/21 Oct/Nov 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 β-particle. Which equation represents this decay? 84 Po 8 5 At –1 β A → + 218 218 0 84 Po –1 β 8 5 At B + → 218 0 218 218 Po 218 At 0 β C → + 8 4 85 – 1 218 Po 0 β 218 At D + → 8 4 – 1 85

1 marks

Answer: C

This question in 0972/21 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 0972/21 Oct/Nov 2022

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

1 marks

Answer: C

This question in 0972/21 Oct/Nov 2022

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 0972/21 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 0972/21 May/June 2023

35 Which change occurs in the nucleus of a radioactive atom during -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 0972/22 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 0972/22 May/June 2023

34 In -particle scattering, -particles are incident on a thin metal foil. Which row describes results from the experiment and a conclusion that the results lead to? results conclusion A most of the -particles most of the atom is empty space pass straight through the foil B most of the -particles the nucleus is very large pass straight through the foil C very few of the -particles most of the atom is empty space pass straight through the foil D very few of the -particles the nucleus is very large pass straight through the foil

1 marks

Answer: A

This question in 0972/21 Oct/Nov 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 0972/21 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 0972/21 Oct/Nov 2023

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 0972/21 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 0972/21 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 0972/22 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 0972/22 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 0972/22 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 0972/22 May/June 2024

34 -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 0972/21 Oct/Nov 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 0972/21 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 0972/21 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 0972/21 Oct/Nov 2024

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 0972/21 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 > *iNe + $B 24 20 4 Na — “oF + 5B 0 Oo WD > 24 20 4 1iNa — 43Al + 5B

1 marks

Answer: A

This question in 0972/21 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 0972/21 May/June 2025

33 239 Pu is an isotope of plutonium. 94 The nucleus can absorb a neutron and then split to form two other nuclei. Two nuclei that form are gold, 207 Au, and phosphorus, 31 P. 79 15 In this reaction, neutrons are also produced. What is the number of neutrons produced when the nucleus splits? A 1 B 2 C 4 D 5

1 marks

Answer: B

This question in 0972/21 Oct/Nov 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 0972/21 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 0972/21 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 0972/21 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 0972/21 Oct/Nov 2025