Lesson 3.8.1.5

3.8.1.5 Nuclear radius Quiz: AQA Physics, Unit 8

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.8.1.5, Nuclear radius: 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. Which expression relates the nuclear radius R to the nucleon number A?

    • R = R0 x A^3, with R0 about 1.2 x 10^-15 m
    • R = R0 x A^(1/2), with R0 about 1.2 x 10^-15 m
    • R = R0 x A, with R0 about 1.2 x 10^-15 m
    • R = R0 x A^(1/3), with R0 about 1.2 x 10^-15 m

  2. What does R proportional to A^(1/3) imply about nuclear density?

    • It is the same for all nuclei only if they have the same radius
    • It increases with mass number, since heavier nuclei are denser
    • It falls as nuclei get larger, since the radius grows
    • It is constant for all nuclei, since volume is proportional to A

  3. What is the typical size of a nuclear radius?

    • about 10^-12 m
    • about 10^-18 m
    • about 10^-15 m
    • about 10^-10 m

  4. Using R0 = 1.2 x 10^-15 m, what is the radius of a copper nucleus with A = 64?

    • 7.7 x 10^-15 m
    • 1.2 x 10^-15 m
    • 4.8 x 10^-15 m
    • 16 x 10^-15 m

  5. Taking R0 = 1.2 x 10^-15 m, what is the approximate density of a copper nucleus with A = 64? Take the nucleon mass as 1.67 x 10^-27 kg.

    • 2.3 x 10^17 kg m^-3
    • 1.0 x 10^3 kg m^-3
    • 2.3 x 10^14 kg m^-3
    • 2.3 x 10^20 kg m^-3

  6. A nucleus with A = 216 has what ratio of radius to a nucleus with A = 27?

    • 8
    • 2
    • 3
    • 1.5

  7. A student claims that the nucleus of lead-208 has twice the radius of calcium-40. Is the claim correct?

    • Yes, the ratio is about 5, and a cube root gives 2
    • Yes, the ratio is 2, since radius is proportional to A
    • No, the ratio is about 1.7, since (208/40)^(1/3) = 1.73
    • No, the ratio is about 5, since radius is proportional to A

  8. A closest-approach estimate gives 4.6 x 10^-14 m for gold, but the nuclear radius is about 7 x 10^-15 m. Why is the closest approach larger?

    • Electrons in the atom add to the radius of the nucleus
    • The de Broglie wavelength of the alpha particle makes it appear bigger
    • Gravitational attraction between the particle and the nucleus increases the apparent radius
    • The alpha particle is stopped by Coulomb repulsion before touching the nucleus, so the estimate is an upper limit on the radius

  9. Why does electron diffraction give a useful measure of nuclear radius?

    • electrons interact with the nuclear charge electromagnetically, and the diffraction pattern depends on the nuclear size
    • electrons only reach the outer shell, so the pattern shows the atom's size
    • electrons are heavier than alpha particles and reach deeper into the nucleus
    • electrons pass through the nucleus and measure its mass directly

  10. Using R0 = 1.2 x 10^-15 m, what is the radius of a tellurium nucleus with A = 125?

    • 25 x 10^-15 m
    • 6.0 x 10^-15 m
    • 1.2 x 10^-15 m
    • 3.0 x 10^-15 m

  11. What is the ratio of the volume of a nucleus with A = 8 to that of a nucleus with A = 1?

    • 64
    • 8
    • 2
    • 1

  12. A nucleus of A = 27 has radius 3.6 x 10^-15 m. What is R0?

    • 0.12 x 10^-15 m
    • 1.2 x 10^-15 m
    • 9.0 x 10^-15 m
    • 3.6 x 10^-15 m

  13. What is the radius of an iron-56 nucleus, using R0 = 1.2 x 10^-15 m?

    • 1.2 x 10^-15 m
    • 6.7 x 10^-15 m
    • 2.8 x 10^-15 m
    • 4.6 x 10^-15 m

  14. Why is nuclear density approximately constant across different nuclei?

    • nucleons become smaller in heavier nuclei
    • nuclear density is set by the electron cloud, which is the same for all atoms
    • radius grows as A^(1/3), so volume grows in direct proportion to the number of nucleons
    • heavier nuclei have proportionally more space between their nucleons

  15. The closest-approach estimate for a 7.7 MeV alpha particle on lead (Z = 82) is used. Which value is closest to the estimate? Use k = 9.0 x 10^9 N m^2 C^-2.

    • 1.5 x 10^-14 m
    • 6.1 x 10^-14 m
    • 3.1 x 10^-15 m
    • 3.1 x 10^-14 m

  16. A nucleus has radius 3.0 fm, and R0 = 1.2 fm. What is its approximate nucleon number?

    • 8
    • 16
    • 25
    • 3

  17. What is the ratio of the volumes of a nucleus with A = 125 and one with A = 1?

    • 25
    • 5
    • 15 625
    • 125

  18. What is the approximate radius of a single proton nucleus (hydrogen-1), using R0 = 1.2 x 10^-15 m?

    • 1.7 x 10^-15 m
    • 1.2 x 10^-10 m
    • 1.2 x 10^-15 m
    • 0.6 x 10^-15 m

  19. What does electron diffraction by a nucleus show in its intensity against angle graph?

    • electrons absorbed by the nucleus at every angle
    • minima whose angles depend on the nuclear size
    • a repeating pattern set by the periodic table
    • reflection only from the outer surface of the nucleus

  20. Nuclear density is about 2.3 x 10^17 kg m^-3. How many times denser is this than water at 1000 kg m^-3?

    • about 2 x 10^14 times
    • about 2 x 10^7 times
    • about 2 x 10^17 times
    • about 2 x 10^3 times

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