Lesson 3.8.1.2

3.8.1.2 Alpha, beta and gamma radiation Quiz: AQA Physics, Unit 8

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.8.1.2, Alpha, beta and gamma radiation: 20 multiple choice questions for the AQA Physics (7408), Unit 8: Nuclear physics (A-level only), written with Revision Ninja.

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The 20 questions

  1. What is an alpha particle?

    • a helium-4 nucleus, made of two protons and two neutrons
    • a high-energy photon with no mass
    • a single electron emitted from the nucleus
    • a proton ejected from the nucleus

  2. What is emitted in beta-minus decay?

    • a photon, emitted as the nucleus de-excites
    • a positron, produced when a proton changes into a neutron
    • an electron, produced when a neutron changes into a proton
    • a proton, produced when a neutron decays

  3. What is gamma radiation?

    • electromagnetic radiation, a photon emitted from an excited nucleus with no change in mass or charge number
    • an electron with a fixed energy emitted from the nucleus
    • a neutron emitted from a nucleus that has decayed
    • a helium nucleus that reduces the mass number by four

  4. Which type of radiation is stopped by a sheet of paper or a few centimetres of air?

    • neutron radiation of low energy
    • alpha
    • beta-minus
    • gamma

  5. Which type of radiation is most ionising per unit distance travelled?

    • gamma, since photons carry the greatest energy
    • beta, since electrons are the lightest particles
    • alpha, since it has a double positive charge and ionises strongly along its short path
    • all of them ionise equally per unit distance

  6. In a magnetic field, how do alpha and beta radiation behave, and what happens to gamma?

    • All three are deflected by the same amount in the same direction
    • Alpha and beta are deflected in opposite directions, and gamma is undeflected
    • Only gamma is deflected, while alpha and beta are not deflected
    • Alpha and beta are deflected in the same direction, and gamma is deflected the most

  7. A count rate of 800 counts per minute is recorded at 0.50 m from a gamma source. What is the expected count rate at 1.0 m?

    • 200 counts per minute
    • 400 counts per minute
    • 1600 counts per minute
    • 100 counts per minute

  8. A count rate of 800 counts per minute is recorded at 0.50 m from a gamma source. What is the expected count rate at 2.0 m?

    • 400 counts per minute
    • 200 counts per minute
    • 50 counts per minute
    • 100 counts per minute

  9. Which radiation is best stopped by a few millimetres of aluminium?

    • alpha
    • gamma
    • very low-energy photons only
    • beta

  10. When measuring count rate from a source, what correction must be applied for background radiation?

    • multiply the count rate by the half-life of the source
    • divide the count rate by the square of the distance only
    • subtract the background count rate from the measured count rate
    • add the background count rate to the measured count rate

  11. A detector records 1200 counts in 60 s from a source, with a background of 180 counts in 60 s. What is the corrected count rate?

    • 17 counts per second
    • 20 counts per second
    • 3.0 counts per second
    • 23 counts per second

  12. If the distance from a gamma source is tripled, what happens to the count rate?

    • It falls to one ninth
    • It falls to one third
    • It falls to one sixth
    • It becomes three times larger

  13. Why is gamma radiation more penetrating than beta radiation?

    • it travels at the speed of sound in the material
    • it has greater mass, so it passes through more material
    • it has no charge and interacts only weakly with matter, so it travels much further through it
    • it has a larger charge so it is more strongly repelled by electrons

  14. Why is an alpha source dangerous inside the body but not greatly hazardous outside it?

    • it travels too fast to damage cells before it stops
    • it is electrically neutral and so cannot ionise any cells
    • it is highly ionising, causing large damage when inside the body, but it is stopped by skin or clothing outside
    • it penetrates deeply outside the body but is harmless when inside

  15. Which statement about the relative hazards of radiation is correct?

    • beta sources are most hazardous inside the body because they are neutral
    • gamma and beta sources are an external hazard, but alpha sources are mainly a hazard when ingested or inhaled
    • alpha sources are the greatest external hazard because they penetrate deepest
    • gamma sources are harmless because photons carry no charge

  16. A gamma source gives 480 counts per minute at 1.0 m. What count rate is expected at 4.0 m?

    • 30 counts per minute
    • 7.5 counts per minute
    • 60 counts per minute
    • 120 counts per minute

  17. A source gives 4000 counts per minute at 2.0 m, with a background of 40 counts per minute. What is the corrected count rate at 1.0 m?

    • 3960 counts per minute
    • 16 000 counts per minute
    • 15 840 counts per minute
    • 8000 counts per minute

  18. Why does gamma emission not change the mass number or the proton number of a nucleus?

    • a gamma photon carries away energy but no mass or charge, so A and Z are unchanged
    • a gamma photon converts a neutron into a proton, raising Z by one
    • a gamma photon carries away a helium nucleus, reducing A by four
    • a gamma photon carries negative charge, so Z falls by one

  19. A beta-minus particle and an alpha particle enter the same magnetic field at right angles. Which statement is correct?

    • Neither curves, because both are forms of radiation
    • They curve in the same direction, because both are positively charged
    • They curve in opposite directions because they have opposite signs of charge
    • Only the beta curves, because the alpha particle is neutral

  20. A gamma source gives a corrected count rate of 2400 counts per second at 0.80 m. What is the rate at 2.0 m?

    • 96 counts per second
    • 600 counts per second
    • 384 counts per second
    • 960 counts per second

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