ConceptConceptDocsDocuments

CAIE A-Level Physics 8.3.2 Two-Source Interference Experiments

Practise interpreting two-source interference experiments with water, sound, light or microwaves, identifying apparatus, observations, reinforcement and cancellation.

Syllabus
2028–2030
Course
Physics 9702
Level
AS

Exam points

  • describe or interpret a two-source interference experiment using water waves, sound, light or microwaves
  • identify the apparatus, source arrangement and observations that demonstrate interference
  • compare how the experiment reveals reinforcement and cancellation in the medium

8.3.2—Experiments that demonstrate two-source interference question 1

[Maximum number: 3]

Question (a)

(a)

Two sources S1\mathrm{S}_{1} and S2\mathrm{S}_{2} of sound waves are positioned as shown in Fig. 5.2.

Fig. 5.2 (not to scale)

Fig. 5.2 (not to scale)

The sources emit coherent sound waves of wavelength 0.85 m . A sound detector is moved parallel to the line S1S2S_{1} S_{2} from a point X to a point Y. Alternate positions of maximum loudness L and minimum loudness Q are detected, as illustrated in Fig. 5.2.

Distance S1XS_{1} X is equal to distance S2XS_{2} X. Distance S2YS_{2} Y is 7.40 m.

[ 3 ]

Question (i)

(i)

State the phase difference between the two waves arriving at the position of minimum loudness Q that is closest to point X.
phase difference =

[ 1 ]

Question (ii)

(ii)

Determine the distance S1YS_{1} Y.
distance = m

[ 2 ]
All question bank results loaded