ConceptConceptDocsDocuments

CAIE A-Level Physics 11.1.1 Alpha-Particle Scattering Evidence

Practise using alpha-scattering paths to infer that atoms are mostly empty space with a small, charged, massive nucleus and concentrated nuclear mass.

Syllabus
2028–2030
Course
Physics 9702
Level
AS

Exam points

  • infer from most alpha-particles passing through, a small fraction being deflected and rare large-angle scattering that the atom is mostly empty space with a very small, charged, massive nucleus
  • use scattering observations to infer the small size, charge and mass concentration of the nucleus

11.1.1—The results of the α-particle scattering experiment the existence and small question 1

[Maximum number: 5]

Fig. 6.1 shows four alpha particles W, X, Y and Z moving towards a gold nucleus that is in thin gold foil.

Fig. 6.1 (not to scale)

Fig. 6.1 (not to scale)

Question (a)

(a)

The paths of particles X and Z are shown.

Complete Fig. 6.1 to show possible paths for particles W and Y.

[ 3 ]

Question (b)

(b)

Describe what may be inferred about the structure of an atom from the path of particle X .

[ 1 ]

Question (c)

(c)

When a beam containing many alpha particles is incident on thin gold foil, nearly all of the alpha particles follow paths that are similar to the path of particle Z .

Describe what may be inferred from this about the structure of an atom.

[ 1 ]
All question bank results loaded