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CAIE A-Level Physics AS 8.1 Stationary Waves Questions

Practise explaining and investigating stationary waves with superposition, nodes, antinodes and resonance, then finding wavelength or phase from data.

Syllabus
2028–2030
Course
Physics 9702
Level
AS

Exam points

  • apply superposition to calculate or sketch resultant displacements and explain constructive/destructive combinations
  • explain and investigate stationary waves using opposite travelling waves, nodes, antinodes and experimental observations
  • determine wavelength and phase information from node/antinode positions or stationary-wave graphs

Covered syllabus points

8.1.1—And use the principle of superposition8.1.2—Experiments that demonstrate stationary waves using microwaves, stretched8.1.3—The formation of a stationary wave using a graphical method, and identify8.1.4—Wavelength may be determined from the positions of nodes or antinodes of a

Question 1

[Maximum number: 1]

Two waves superpose. A resultant wave pattern is formed.
Which statement about the two waves must be correct?

A

They have the same amplitude.

B

They are of the same type.

C

They are transverse waves.

D

They travel in opposite directions.

Question 2

[Maximum number: 1]

A stationary sound wave is set up between a loudspeaker and a wall.
A microphone is connected to a cathode-ray oscilloscope (CRO) and is moved along a line directly between the loudspeaker and the wall. The amplitude of the trace on the CRO rises to a maximum at a position X , falls to a minimum and then rises once again to a maximum at a position Y.

The distance between X and Y is 33 cm . The speed of sound in air is 330 m s−1330 \mathrm{~m} \mathrm{~s}^{-1}.
Which diagram could represent the CRO trace of the sound received at X?

A
Figure for Question 2 — CAIE A-Level Physics AS — Option A
B
Figure for Question 2 — CAIE A-Level Physics AS — Option B
C
Figure for Question 2 — CAIE A-Level Physics AS — Option C
D
Figure for Question 2 — CAIE A-Level Physics AS — Option D

Question 3

[Maximum number: 7]

Question (a)

(a)

A tube is open at both ends. A loudspeaker, emitting sound of a single frequency, is placed near one end of the tube, as shown in Fig. 3.1.

Fig. 3.1

Fig. 3.1

The speed of the sound in the tube is 340 ms−1340 \mathrm{~ms}^{-1}. The length of the tube is 0.60 m .
A stationary wave is formed with an antinode A at each end of the tube and two antinodes inside the tube.

[ 7 ]

Question (i)

(i)

State what is meant by an antinode of the stationary wave.

[ 1 ]

Question (ii)

(ii)

State the distance between a node and an adjacent antinode.

distance =m [1]
[ 1 ]

Question (iii)

(iii)

Determine, for the sound in the tube,
1. the wavelength,
wavelength = m
2. the frequency.
frequency = Hz

[ 3 ]

Question (iv)

(iv)

Determine the minimum frequency of the sound from the loudspeaker that produces a stationary wave in the tube.
minimum frequency = Hz

[ 2 ]
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