IGCSEPhysicsCambridge (CIE)Exam Questions5. Nuclear PhysicsRadioactivity

Radioactivity (Cambridge (CIE) IGCSE Physics): Exam Questions

Exam code: 0625 & 0972

3 hours51 questions

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1
1 mark

Radioactive materials are usually stored in containers lined with metal. This is done to reduce the amount of radiation being emitted, to protect people nearby.

What type of metal is used for this purpose?

  • Lead

  • Aluminium

  • Steel

  • Copper

Choose your answer

2
1 mark

A student has three radioactive sources X, Y and Z. They devised the following experiment to determine what type of radiation each source is emitting. 

q2-easy-mcq-5-2-radioactivity-cie-igcse-physics

The student found that the radiation from X was stopped by a sheet of paper, Y was partially stopped by a few cm of lead and Z was stopped by a few mm of aluminium.

Which of the following correctly identifies each type of radiation

 

X

Y

Z

A

α-particle

β-particle

γ-ray

B

α-particle

γ-ray

β-particle

C

γ-ray

β-particle

α-particle

D

β-particle

γ-ray

α-particle

    Choose your answer

    3
    1 mark

    Which statement is not a method used to minimise the risk caused by working with radioactive sources.

    • Store the sources in lead-lined boxes.

    • Minimise the amount of time spent handling the sources.

    • Keep the source cold.

    • Keep the source as far away as possible, for example, using a pair of tongs.

    Choose your answer

    4
    1 mark

    Which statement about α-particles is correct?

    • α-particles consist of two protons and two electrons.

    • α-particles are the most penetrating type of radiation.

    • α-particles are a type of electromagnetic radiation.

    • α-particles are highly ionising.

    Choose your answer

    5
    1 mark

    There are three main types of radiation which may be emitted during radioactive decay: α-particles, β-particles and γ-rays.

    Which of the following statements about these types of emissions is true?

    • α-particles are the only type of radiation to have a charge

    •  γ-rays are stopped by a sheet of paper

    • β-particles have the greatest ionising effect

    • γ-rays are the most penetrating

    Choose your answer

    6
    1 mark

    Which statement about the radioactive decay of a substance is correct?

    • It cannot be predicted when a particular nucleus will decay.

    • Placing a radioactive substance inside a lead-lined box prevents it from decaying.

    • The decay always produces poisonous gases.

    • The rate of decay increases if the substance is dissolved in water.

    Choose your answer

    7
    1 mark

    Background radiation is the radiation that is always present in the environment around us.

    Which list contains only natural sources of background radiation?

    • cosmic rays, radon gas, medical X-rays

    • cosmic rays, radon gas, rocks and buildings

    • food and drink, nuclear power stations, cosmic rays

    • mobile phones, radon gas, rocks and buildings

    Choose your answer

    1
    1 mark

    A student carried out an experiment to find the half-life of a radioactive substance. Their results are shown in the table below.

    Time(seconds)

    Count-rate from source(counts per second)

    0

    300

    20

    200

    40

    150

    60

    100

    80

    75

    What is the half-life of this substance?

    • 20 seconds

    • 40 seconds

    • 60 seconds

    • 80 seconds

    Choose your answer

    2
    1 mark

    Extended tier only

    Strontium-90 is a radioactive substance with the nuclide symbol S presubscript 38 presuperscript 90 r .

    It decays by emitting radiation, as shown by the following equation.

    S presubscript 38 presuperscript 90 r space rightwards arrow Y presubscript 39 presuperscript 90 space plus space ?

    What is missing in this equation?

    • α-particle

    • Neutron

    • γ-ray

    • β-particle

    Choose your answer

    3
    1 mark

    Extended tier only

    A radioactive nucleus emits a β-particle.

    What happens to the proton number and the nucleon number of this nucleus?

     

    Proton number

    Nucleon number

    A

    increases by 1

    stays the same

    B

    stays the same

    decreases by one

    C

    decreases by 2

    decreases by 4

    D

    decreases by 1

    stays the same

      Choose your answer

      4
      1 mark

      The count rate from a radioactive isotope is recorded every hour. The count rate is corrected for background radiation. The table shows the readings.

      time / hours

      0

      1

      2

      3

      4

      5

      corrected count rate / counts/s

      1200

      990

      816

      673

      555

      458

      What estimate of the half-life of the isotope can be obtained from the readings in the table?

      • between 1 and 2 hours

      • between 2 and 3 hours

      • between 3 and 4 hours

      • between 4 and 5 hours

      Choose your answer

      5
      1 mark

      Extended tier only

      A nucleus of uranium ( begin mathsize 24px style U presubscript 92 presuperscript 238 end style) is unstable and decays by emitting an α-particle. 

      Which equation correctly describes this process?

      • straight U presubscript 92 presuperscript 238 space rightwards arrow space straight alpha presubscript 2 presuperscript 4 space plus space Th presubscript 90 presuperscript 234

      • straight U presubscript 92 presuperscript 238 space rightwards arrow space straight alpha presubscript 2 presuperscript 4 space plus space straight U presubscript 90 presuperscript 234

      • straight U presubscript 92 presuperscript 238 space plus space straight alpha presubscript 2 presuperscript 4 space rightwards arrow space Th presubscript 90 presuperscript 234

      • straight U presubscript 92 presuperscript 238 space rightwards arrow space straight alpha presubscript 2 presuperscript 4 space plus space Ra presubscript 88 presuperscript 234

      Choose your answer

      6
      1 mark

      Which statement about 𝝰-particles and 𝛃-particles is correct?

      • 𝝰-particles are less ionising than 𝛃-particles.

      • 𝝰-particles are more penetrating than 𝛃-particles.

      • 𝝰-particles have greater mass than 𝛃-particles.

      • 𝝰-particles have the same charge as 𝛃-particles.

      Choose your answer

      7
      1 mark

      Extended Tier Only

      The diagram shows emissions from a source passing into the electric field between two charged plates.

      Diagram of charged particle deflection using electric fields; particles from a source curve towards a positively charged plate, away from a negative plate.

      What is emitted by this source?

      • neutrons and ɣ-rays only

      • 𝝰-particles and 𝛃-particles only

      • 𝝰-particles and ɣ-rays only

      • 𝛃-particles and ɣ-rays only

      Choose your answer

      8
      1 mark

      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? 

      • 750 counts per second

      • 1500 counts per second

      • 2000 counts per second

      • 3000 counts per second

      Choose your answer

      9
      1 mark

      Extended Tier Only

      The diagram shows a stream of -particles travelling in a line that passes between the poles of a magnet.

      Diagram showing beta particles moving towards a magnetic field between the north (N) and south (S) poles of a magnet, indicated by boxes.

      In which direction will the -particles be deflected by the magnet?

      • towards the N pole

      • towards the S pole

      • into the page

      • out of the page

      Choose your answer

      10
      Sme Calculator
      1 mark

      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?

      • 50 cpm

      • 70 cpm

      • 190 cpm

      • 270 cpm

      Choose your answer

      11
      Sme Calculator
      1 mark

      Which statement about the random decay of the nuclei in a sample of uranium-238 is correct?

      • The probabilities of an alpha-particle, a beta- particle or a gamma ray being emitted from a nucleus in the sample are equal.

      • The probability of a nucleus in the sample decaying decreases as time passes.

      • The probability of a nucleus decaying in any ten-minute interval is the same for all the nuclei in the sample.

      • The probability of a nucleus in the sample decaying increases as time passes.

      Choose your answer

      12
      1 mark

      The graph shows how the number of nuclei from a radioactive source changes with time.

      A decay curve starting at 400 nuclei at time = 0. The number of nuclei drops to 200 nuclei after 1 hour and 100 nuclei after 2 hours.

      What is the half-life of the radioactive source?

      • 1 hour

      • 2 hours

      • 4 hours

      • 8 hours

      Choose your answer

      13
      1 mark

      A nucleus of radium-226 (Ra presubscript 88 presuperscript 226) undergoes alpha decay.

      What are the nucleon number and the proton number of the new nucleus formed?

      nucleon number

      proton number

      A

      222

      86

      B

      222

      88

      C

      224

      87

      D

      230

      90

        Choose your answer

        14
        1 mark

        A radioactive source is used inside the body to diagnose a medical condition.

        Which properties should the radioactive source have?

        • It should emit alpha particles and have a long half-life.

        • It should emit beta particles and have a short half-life.

        • It should emit gamma rays and have a long half-life.

        • It should emit gamma rays and have a short half-life.

        Choose your answer

        1
        1 mark

        Extended tier only

        Radioactive sources are often used in industry as part of manufacturing processes. The diagram below shows radiation being used to measure the thickness of a sheet of aluminium foil. The detector feeds back to the rollers to adjust the thickness.

        q1-hard-mcq-5-2-radioactivity-cie-igcse-physics

        What type of radiation would be the most suitable for this purpose?

        • α-particles

        • β-particles

        • γ-rays

        • All of the above

        Choose your answer

        2
        1 mark

        The count rate of a radioactive material is measured using a detector. The reading on the detector is 88 counts per second. The background count rate is 40 counts per second.

        The half-life of the radioactive substance is 12 hours. What is the reading on the detector after 24 hours?

        • 22

        • 12

        • 44

        • 52

        Choose your answer

        3
        1 mark

        A radioactive substance has a half-life of 4 days. 

        It is currently emitting 8000 β-particles per minute.

        How many β-particles will it emit per minute after 12 days?

        • 4000

        • 2000

        • 1000

        • 667

        Choose your answer

        4
        1 mark

        Extended tier only

        Beta and gamma radiation are passed through two charged metal plates as shown in the diagram below.

        q4-hard-mcq-5-2-radioactivity-cie-igcse-physics

        Which direction, if any, would the β-particles and γ-rays be deflected?

         

        β-particles

        γ-rays

        A

        into the page

        continue straight

        B

        towards the negative plate

        out of the page

        C

        continue straight

        towards the negative plate

        D

        towards the positive plate

        continue straight

          Choose your answer

          5
          1 mark

          The graph shows the activity of a radioactive source over a period of time.

          5-2-5h-half-life-graph

          What is the half-life of the source?

          • 5 seconds

          • 5 minutes

          • 300 seconds

          • 300 minutes

          Choose your answer

          6
          Sme Calculator
          1 mark

          The count rate due to a sample of a radioactive isotope is measured for 80 minutes.

          time

          (minutes)

             count rate  
          (counts / second)

          0

          480

          20

          380

          40

          300

          60

          240

          80

          190

          What is the half-life of the isotope?

          • 20 minutes

          • 40 minutes

          • 60 minutes

          • 80 minutes

          Choose your answer