Pearson Edexcel International GCSE (9–1) · PHYSICS · Unit
Waves
356 practice questions
Topics covered
Practice questions
191–200 of 356
Question 191
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 192
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 193
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 194
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 195
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 196
3 marks · Normal
Answer and see the solution →Describe a practical experiment you could carry out to demonstrate the Doppler effect using sound.
Question 197
4 marks · Easy
Answer and see the solution →A bell is rung underwater, and the sound travels to a diver who is standing a certain distance away.
(a)[2 marks]State whether sound waves in water are longitudinal or transverse. Explain your answer.
(b)[2 marks]The sound wave in water has a frequency of 800 Hz and a wavelength of 1.9 m. Calculate the speed of sound in water using the wave equation.
Question 198
4 marks · Easy
Answer and see the solution →A ripple tank is used to demonstrate water waves. The table below shows the number of waves passing a fixed point in different time intervals.
Number of waves observed in 10 s intervals. Interval (s) Number of waves 10 25 10 30 (a)[1 mark]Calculate the frequency of the waves in the first experiment (25 waves in 10 seconds).
(b)[1 mark]State the definition of frequency.
(c)[2 marks]If the wavelength of these water waves is measured to be 0.048 m, calculate the wave speed for the first experiment.
Question 199
4 marks · Easy
Answer and see the solution →A train travels towards an observer while sounding its whistle. The observer notices the pitch of the sound is higher than when the train is stationary.
(a)[1 mark]What is the name given to this effect?
(b)[2 marks]Explain why the observer hears a higher pitch as the train approaches.
(c)[1 mark]State whether the wavelength of the sound increases or decreases for the observer as the train gets closer.
Question 200
5 marks · Normal
Answer and see the solution →A ripple tank is used to study water waves. When the frequency of the motor is increased, the spacing of the wavefronts changes.
(a)[2 marks]Describe, using the terms wavelength and frequency, how the spacing between wavefronts changes as the frequency is increased.
(b)[3 marks]The distance from a crest to the next crest in the tank is measured to be . The frequency of vibration is . Calculate the speed of the water waves. Give your answer in .