Pearson Edexcel International GCSE (9–1) · PHYSICS · Section
The Doppler Effect
16 practice questions
Practice questions
1–8 of 8 · Normal
Question 1
1 mark · Normal
Answer and check →Which statement best describes the Doppler effect?
- A.It is the apparent change in frequency of a wave due to the movement of the source.
- B.It describes the reflection of waves at a boundary.
- C.It is the process of splitting white light into its component colours.
- D.It explains why sound cannot travel through a vacuum.
Question 2
2 marks · Normal
Answer and see the solution →Describe what happens to the wavelength and frequency of sound waves ahead of a car as it moves towards a stationary observer.
Question 3
3 marks · Normal
Answer and see the solution →A train travels towards a platform at high speed.
(a)[2 marks]Explain how the frequency of the sound heard by a person standing on the platform compares to the frequency emitted by the train.
(b)[1 mark]If the train then stops, what happens to the sound's frequency for the person on the platform?
Question 4
4 marks · Normal
Answer and see the solution →A police car moves directly towards a stationary observer at a speed of 30 m/s. The siren emits a sound with a frequency of 800 Hz. The speed of sound in air is 340 m/s.
(a)[1 mark]Explain why the observer hears a higher frequency as the car approaches.
(b)[3 marks]Calculate the observed frequency of the siren heard by the observer. Give your answer to 2 significant figures.
Question 5
3 marks · Normal
Answer and see the solution →A graph below shows how the frequency of a sound heard by an observer changes as a vehicle passes by:
(a)[1 mark]Describe the main feature shown on the graph.
(b)[2 marks]Explain, using the Doppler effect, why the frequency drops suddenly at around t = 5 s.
Question 6
3 marks · Normal
Answer and see the solution →A football referee blows the whistle while jogging towards some players. The players report hearing a whistle that is slightly higher in pitch than normal.
Explain, using the idea of wavefronts, why the frequency of sound is heard as higher.
Question 7
2 marks · Normal
Answer and see the solution →Give one everyday example of the Doppler effect with sound, and briefly explain how it is noticed.
Question 8
3 marks · Normal
Answer and see the solution →Describe a practical experiment you could carry out to demonstrate the Doppler effect using sound.