Pearson Edexcel International GCSE (9–1) · PHYSICS · Section
The Doppler Effect
16 practice questions
Practice questions
11–16 of 16
Question 11
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 12
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 13
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 14
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 15
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 16
3 marks · Normal
Answer and see the solution →Describe a practical experiment you could carry out to demonstrate the Doppler effect using sound.