A-LevelPhysicsNuclear physics9702/22 · Feb/Mar 2018 · Q66 Marks
A sample of a radioactive isotope emits a beam of β⁻ radiation.
- (a)State the change, if any, to the number of neutrons in a nucleus of the sample that emits a β⁻ particle.[1]
- (b)The number of β⁻ particles passing a fixed point in the beam in a time of 2.0 minutes is 9.8 x 10¹⁰. Calculate the current, in pA, produced by the beam of β⁻ particles.[3]
- (c)Suggest why the β⁻ particles are emitted with a range of kinetic energies.[2]
Mark scheme
Marking points from the official mark scheme (Feb/Mar 2018). The mark or mark type is shown in brackets.
- [A1] -1 / decreases by 1
- [C1] I = Q / t or Ne / t
- = (9.8×10^10 × 1.6×10⁻¹⁹) / (2.0 × 60)
- [C1]
- [A1] = 130 pA
- [C1] antineutrino(s) (emitted) / other particle(s) (emitted)
- [A1] energy / momentum shared with antineutrino(s)
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