Waves: Exam questions
1. [2007 OL]
The diagram shows the waveform of a musical note.
What is the name given to (i) the distance A, (ii) height B?
2. [2007 OL]
Explain what is meant by the frequency of a wave.
3. [2005 OL]
What is meant by the amplitude of a wave?
4. [2005][2006 OL]
Explain the difference between longitudinal and transverse waves.
5. [2005 OL]
A wave motion has a frequency of 5 hz and a wavelength of 200 m. Calculate the speed of the wave.
6. [2007 OL]
A tin-whistle produces a note of 256 Hz. Calculate the wavelength of this note.
7. [2006 OL]
(i) A ship detects the seabed by reflecting a pulse of high frequency sound from the seabed. The sound pulse is detected 0.4 s after it was sent out and the speed of sound in water is 1500 m s–1.
Calculate the time taken for the pulse to reach the seabed.
(ii) Calculate the depth of water under the ship.
(iii) Calculate the wavelength of the sound pulse when its frequency is 50 000 Hz.
8. [2004 OL][2002 OL][2005 OL][2009]
Explain the term diffraction.
9. [2004 OL][2005 OL]
Explain the term interference.
10. [2008]
Why does diffraction not occur when light passes through a window?
11. [2006]
A sound wave is diffracted as it passes through a doorway but a light wave is not. Explain why.
12. [2002]
Explain the term constructive interference.
13. [2002]
Explain the term coherent sources.
14. [2007]
What is the condition necessary for destructive interference to take place when waves from two coherent sources meet?
15. [2004 OL]
(i) The diagram shows a stationary wave (standing wave) on a vibrating stretched string.
What is the name given to the points on the string marked (i) X, (ii) Y?
(ii) How many wavelengths are contained in the distance marked L?
(iii) A note of wavelength 1.4 m is produced from a stretched string. If the speed of sound in air is 340 m s−1, calculate the frequency of the note.
16. [2006]
A stretched string of length 80 cm has a fundamental frequency of vibration of 400 Hz.
What is the speed of the sound wave in the stretched string?
17. [2005]
(i) The diagram shows a guitar string stretched between supports 0.65 m apart.
The string is vibrating at its first harmonic. The speed of sound in the string is 500 m s–1.
What is the frequency of vibration of the string?
(ii) Draw a diagram of the string when it vibrates at its second harmonic.
(iii) What is the frequency of the second harmonic?
18. [2007]
(i) Radio waves of frequency 30 kHz are received at a location 1500 km from a transmitter.
The radio reception temporarily “fades” due to destructive interference between the waves travelling parallel to the ground and the waves reflected from a layer (ionosphere) of the earth’s atmosphere, as indicated in the diagram.
Calculate the wavelength of the radio waves.
(ii) What is the minimum distance that the reflected waves should travel for destructive interference to occur at the receiver?
(iii) The layer at which the waves are reflected is at a height h above the ground.
Calculate the minimum height of this layer for destructive interference to occur at the receiver.
The Doppler Effect
19. [2008 OL]
The pitch of a note emitted by the siren of a fast moving ambulance appears to change as it passes a stationary observer. Name this phenomenon.
20. [2008][2007][2006][2003][2002]
What is the Doppler Effect?
21. [2007][2003][2008 OL]
Explain, with the aid of labelled diagrams, how the Doppler Effect occurs.
22. [2002 OL]
Give an example of the Doppler Effect.
23. [2008][2003][2004 OL][2007 OL]2008 OL]
Give two applications of the Doppler Effect.
24. [2005]
It is noticed that the frequency of the received radio signal changes as the satellite orbits Saturn. Explain why.
25. [2008]
A rally car travelling at 55 m s–1 approaches a stationary observer. As the car passes, its engine is emitting a note with a pitch of 1520 Hz. What is the change in pitch observed as the car moves away?
26. [2003]
(i) Bats use high frequency waves to detect obstacles. A bat emits a wave of frequency 68 kHz and wavelength 5.0 mm towards the wall of a cave. It detects the reflected wave 20 ms later.
Calculate the speed of the wave.
(ii) If the frequency of the reflected wave is 70 kHz, what is the speed of the bat towards the wall?
27. [2007]
(i) The red line emitted by a hydrogen discharge tube in the laboratory has a wavelength of 656 nm.
The same red line in the hydrogen spectrum of a moving star has a wavelength of 720 nm.
Is the star approaching the earth? Justify your answer.
(ii) Calculate the frequency of the red line in the star’s spectrum
(iii) Calculate the speed of the moving star
