CAIE IGCSE Physics 3.4 Sound Question Bank

Practise interpreting sound as a wave, including frequency range, pitch, loudness, speed in air, echoes and longitudinal features.

Exam points

use wave diagrams to label compressions, rarefactions, amplitude and frequency changes
state the audible frequency range and compare it with ultrasound above 20 kHz
apply the speed of sound in air to simple timing, distance or echo measurements

Covered syllabus points

3.4.1—Production of sound by vibrating 3.4.2—Longitudinal nature of sound waves 3.4.3—Approximate range of frequencies 3.4.4—A medium is needed to transmit sound 3.4.5—Speed of sound in air is approximately 3.4.6—Method involving a measurement of 3.4.7—Changes in amplitude and frequency 3.4.8—An echo as the reflection of sound 3.4.9—Ultrasound as sound with a frequency 3.4.10—Compression and rarefaction 3.4.11—That, in general, sound travels faster 3.4.12—Uses of ultrasound in non- destructive

[Maximum number: 3]

Fig. 4.1 shows a loudspeaker that is producing a sound wave in air of frequency 15000 Hz .

Fig. 4.1

Describe how the cone of the loudspeaker produces this sound.

[Maximum number: 1]

A candle flame is placed in front of a loudspeaker.
The loudspeaker produces a sound wave that causes air particles to vibrate. The vibrating air particles make the candle flame vibrate in the same direction as the air particles.

Figure for Question 3.4 Sound question 2 — CAIE IGCSE Physics

Which row shows the direction of vibration of the candle flame and the nature of sound waves?

direction of

vibration

nature of

sound waves

$\square$

longitudinal

$\square$

transverse

$\longrightarrow$

longitudinal

$\longrightarrow$

transverse

[Maximum number: 2]

A loudspeaker produces a sound wave in air. The distance between the centre of a compression and the centre of a neighbouring rarefaction is 0.10 m .

(a)

State a typical value for the speed of sound in air.

[ 1 ]

any value in range from $330 \mathrm{~m} / \mathrm{s} \leqslant$ value $\leqslant 350 \mathrm{~m} / \mathrm{s}$

B1

(b)

Explain whether the sound from the loudspeaker is audible to a human with normal hearing.

[ 1 ]

audible/yes/it is OR inaudible / no / it isn't consistent with value in 5(c)(i)

AND

consistent explanation with reference to $20(\mathrm{~Hz}) \leqslant$ normal range of human hearing $\leqslant 20000(\mathrm{~Hz})$

B1

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Covered syllabus points

3.4 Sound question 1

3.4 Sound question 2

3.4 Sound question 3

Question (a)

Question (b)