CAIE A-Level Physics 8.1.4 Measuring Stationary-Wave Wavelength

Practise determining wavelength from adjacent nodes or antinodes in a stationary wave, using the pattern geometry to calculate related distances.

Exam points

determine wavelength from the separation of adjacent nodes or adjacent antinodes in a stationary wave
use node or antinode positions and the geometry of the pattern to calculate wavelength or a related distance

[Maximum number: 4]

(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

The speed of the sound in the tube is $340 \mathrm{~ms}^{-1}$ . 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.

[ 4 ]

(i)

State the distance between a node and an adjacent antinode.

distance =m [1]

[ 1 ]

distance $=0.10 \mathrm{~m}$

B1

(ii)

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

[ 3 ]

1. $\lambda=0.60 / 1.5$ $=0.40 \mathrm{~m}$

A1

2. $v=f \lambda$

C1

$\begin{aligned} f =340 / 0.40 =850 \mathrm{~Hz} \end{aligned}$

A1

All question bank results loaded

8.1.4—Wavelength may be determined from the positions of nodes or antinodes of a question 1

Question (a)

Question (i)

Question (ii)