CIE iGCSE Co-Ordinated Science P3.4 Sound Exam Style Questions Paper 1
Question
Which statement about sound is correct?
A An echo is produced by refraction of sound waves.
B The amplitude of a sound wave affects the pitch of a sound.
C The approximate range of audible frequencies for a human is 20 Hz–20kHz.
D Sound waves travel more quickly in a vacuum than in air.
▶️Answer/Explanation
Ans : C
Question
Two students conduct an experiment to determine the speed of sound in air.
They stand 639 m apart.
One student hits two blocks of wood together while the other uses a stop-watch to time how long
it takes for the sound to reach him.
It takes 1.80 s for the sound to reach the second student.
What is the speed of sound in air, calculated using these results?
(A) 330 m/s
(B) 355 m/s
(C) 710 m/s
(D) 1150 m/s
▶️Answer/Explanation
Ans : B
Question
The diagram is a displacement–time graph for the molecules in air as a sound wave passes.
The graphs below are drawn to the same scale.
Which graph represents a quieter sound with a higher pitch?
▶️Answer/Explanation
Ans : D
Question
A man stands 420 m away from a high wall. He bangs a drum once and starts a stop-watch at the
same time. When he hears an echo from the wall, the stop-watch reads 2.4 s.
What is the speed of sound, calculated from this information?
(A) 87.5 m / s (B) 175 m / s (C) 330 m / s (D) 350 m / s
▶️Answer/Explanation
Ans : D
Question
The sound heard from the siren of a police car becomes quieter and lower pitched as the car moves away from an observer.
Which row describes what happens to the amplitude and frequency of the sound wave heard by the observer?
▶️Answer/Explanation
Ans: A
Question
The amplitude of a sound wave increases, and the frequency of the wave decreases.
What is the effect on the loudness of the sound and on the pitch of the sound?
▶️Answer/Explanation
Ans: B
Question
Which change to a sound wave makes the sound louder?
(A) decreasing the amplitude
(B) decreasing the wavelength
(C) increasing the amplitude
(D) increasing the wavelength
▶️Answer/Explanation
Ans : C
Question
A student claps his hands once when standing 100 m away from a large wall.
The speed of sound in air is 330 m / s.
How long after clapping does the student hear an echo?
(A) 0.30 s (B) 0.61 s (C) 1.7 s (D) 3.3 s
▶Answer/Explanation
Ans : B
Question
An electric bell is suspended by a rubber band in a glass jar. The hammer hits the bell and makes it ring.
A pump removes air from the jar. The hammer still hits the bell but no sound can be heard.
Why does this happen?
(A) A medium is needed to transmit sound waves.
(B) The bell cannot vibrate in a vacuum.
(C) The pitch of the sound is now outside the range of human hearing.
(D) There cannot be an electric current in a vacuum.
▶️Answer/Explanation
Ans: A
Question
The diagrams represent two different sound waves, P and Q, drawn to the same scale.
▶️Answer/Explanation
Ans: D
Question
Sound travels at different speeds in water, in steel and in air. Each row in the table gives the three speeds at room temperature. Which row gives the speeds in the correct columns?
▶️Answer/Explanation
Answer: C
Explanation: Sound travels fastest in solids (steel), slower in liquids (water), and slowest in gases (air). Therefore, the correct order of speeds is 1500 m/s (water), 4500 m/s (steel), and 300 m/s (air). The correct answer is C.
Question
A worker in a quarry stands 0.90 km away from an explosion. She sees the explosion 3.0 s before she hears the sound of the explosion. Using this information, what value can be determined for the speed of sound?
A. 300 m/s
B. 600 m/s
C. 2700 m/s
D. 5400 m/s
▶️Answer/Explanation
Answer: A. 300 m/s.
Explanation: The speed of sound can be calculated using the formula: speed = distance / time. The distance is 0.90 km (900 m), and the time is 3.0 s. Therefore, speed = 900 m / 3.0 s = 300 m/s.
Question
A person stands 320 m away from a cliff and shouts. He hears an echo from the cliff 2.0 s later. What is the speed of sound in the air?
A) 160 m/s
B) 300 m/s
C) 320 m/s
D) 640 m/s
▶️Answer/Explanation
Answer: C) 320 m/s
Explanation: The speed of sound is calculated using the formula: \[ \text{Speed} = \frac{\text{Distance}}{\text{Time}} \] The sound travels to the cliff and back, so the total distance is \( 2 \times 320\, \text{m} = 640\, \text{m} \). The time taken is 2.0 s, so: \[ \text{Speed} = \frac{640\, \text{m}}{2.0\, \text{s}} = 320\, \text{m/s} \]
Question
The sound heard from the siren of a police car becomes louder and higher pitched as the car approaches an observer. What happens to the amplitude and what happens to the frequency of the sound wave heard by the observer?
| amplitude | frequency | |
|---|---|---|
| A | decreases | decreases |
| B | decreases | increases |
| C | increases | decreases |
| D | increases | increases |
▶️Answer/Explanation
Answer: D) increases, increases
Explanation: As the police car approaches, the sound waves are compressed, leading to an increase in both the amplitude (loudness) and frequency (pitch) of the sound heard by the observer.
Question
The amplitude of a sound wave increases and the frequency decreases. What happens to the loudness and what happens to the pitch of the sound?
A. The sound becomes louder and higher pitched.
B. The sound becomes louder and lower pitched.
C. The sound becomes quieter and higher pitched.
D. The sound becomes quieter and lower pitched.
▶️Answer/Explanation
Answer: B
Explanation: An increase in amplitude results in a louder sound, while a decrease in frequency results in a lower pitch. Therefore, the sound becomes louder and lower pitched.
Question
A person stands 80 m from a high wall and claps his hands. He hears an echo 0.50 s later. Using this information, how is the speed of sound in air calculated?
A. \(\frac{(0.50 \times 2)}{80} \, \text{m/s}\)
B. \(\frac{0.50}{(80 \times 2)} \, \text{m/s}\)
C. \(\frac{(80 \times 2)}{0.50} \, \text{m/s}\)
D. \(\frac{80}{0.50} \, \text{m/s}\)
▶️Answer/Explanation
Answer: C. \(\frac{(80 \times 2)}{0.50} \, \text{m/s}\)
Explanation: The sound travels to the wall and back, so the total distance is \( 80 \, \text{m} \times 2 = 160 \, \text{m} \). The speed of sound is calculated as distance divided by time: \( \frac{160 \, \text{m}}{0.50 \, \text{s}} = 320 \, \text{m/s} \).
Question
Which row gives the properties of a sound wave that affect the pitch and the loudness of a sound?
| pitch | loudness | |
|---|---|---|
| A | amplitude | amplitude |
| B | amplitude | frequency |
| C | frequency | amplitude |
| D | frequency | frequency |
▶️Answer/Explanation
Answer: C
Explanation: The pitch of a sound is determined by its frequency, while the loudness is determined by its amplitude. Therefore, the correct row is C, where frequency affects pitch and amplitude affects loudness.
Question
A sports field is next to a large school building. A student at the far side of the sports field sees a groundsman hit a pole with a hammer.
After the hammer hits the pole, the student hears two bangs.
Why does the student hear two bangs?
▶️Answer/Explanation
Answer: C
Explanation: The first bang is the sound reaching the student directly, and the second bang is the sound reflected off the school building, which takes longer to reach the student.