1. General Properties of WAVE
Name: ____________________ ( )
Class: _____ Date:_____________
General Properties of WAVE
Sec 3 Exp
Science PHYSICS
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2. Name: ____________________ ( )
Class: _____ Date:_____________
What is a Wave?
Wave is a mechanism that carries energy from one point to another.
A wave is created by vibrations or oscillations of objects or substances.
Waves carry energy from one point of vibrations or oscillations to another.
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3. Name: ____________________ ( )
Class: _____ Date:_____________
2 Types of Waves
TRANSVERSE
LONGITUDINAL
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4. Name: ____________________ ( )
Class: _____ Date:_____________
Transverse waves
Waves that travel in a direction perpendicular to the direction of vibration of particles.
This means that particles of transverse wave only moves up and down, while wave travel sideways.
Some examples are rope waves, water waves, light waves and radio waves.
Direction of wave
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5. Name: ____________________ ( )
Class: _____ Date:_____________
Transverse Wave
Transverse wave in air. Direction of wave is from left to right.
Notice how the air particles are vibrating with respect to the
direction of wave motion. The air particles are just vibrating
up and down about their fixed positions as the wave moves
from left to right.
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6. Name: ____________________ ( )
Class: _____ Date:_____________
Longitudinal Waves
Waves that travel in the same direction as the direction of vibration of particles.
Particles of longitundinal waves move side-to-side in a direction parallel to direction of wave.
Some examples are sound waves and waves produced by springs.
Direction of wave
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7. Name: ____________________ ( )
Class: _____ Date:_____________
Longitudinal Wave
Longitudinal wave in air. Direction of wave is from left to right.
Notice how the air particles are vibrating with respect to the
direction of wave motion. Although it appears at first glance that
groups of air particles are moving from left to right, if you look
closely, the air particles are in fact just vibrating about a fixed position.
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8. Key point 1! for ALL wave motion
Name: ____________________ ( )
Class: _____ Date:_____________
During wave motion, the particles are NOT transferred from one point to another.
They just vibrate about their fixed or neutral position.
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9. Name: ____________________ ( )
Class: _____ Date:_____________
Terms used in waves
Crests
Troughs
Displacement
Amplitude
Wavelength
Frequency
Period
Wavefront
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10. Name: ____________________ ( )
Class: _____ Date:_____________
Displacement /m
Crests
wavelength
amplitude
Distance/m
amplitude
wavelength
Troughs
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11. Properties of Wave Motion
Name: ____________________ ( )
Class: _____ Date:_____________
Properties of Wave Motion
Crest: The highest point of a transverse wave.
Trough: The lowest point of a transverse wave.
Amplitude: Maximum displacement from rest or central position. Unit: meter (m).
Displacement has positive and negative values. Normally when particles moves upwards it’s positive. When downwards its negative.
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12. Name: ____________________ ( )
Class: _____ Date:_____________
Describing a wave:
Wavelength: Shortest distance between two ( λ ) points on the wave that are in phase. Unit: meter (m)
Distance between two troughs.
Distance between two crests.
(In phase = both particles move in the same direction, at the same speed and have the same displacement from rest position.)
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13. Name: ____________________ ( )
Class: _____ Date:_____________
Describing a wave:
Frequency: Number of complete waves ( f ) produced in one second.
Unit: Hertz (Hz)
Period: Time taken to produce one ( T ) complete wave. Unit: seconds (s)
Inverse of frequency
(i.e. T = 1 / f )
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14. Name: ____________________ ( )
Class: _____ Date:_____________
Describing a wave:
Wave speed: The distance travelled by a wave (v) in one second.
SI unit: m /s
Wavefront: An imaginary line on a wave that joins all points which have the same
phase of vibration.
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15. Name: ____________________ ( )
Class: _____ Date:_____________
Quick Check
A boy sings as he plays with a rope. He vibrates one end of the rope up and down repeatedly, while the other end is fixed to a wall.
What type of wave is obtained in the rope?
Transverse
Define transverse wave.
A wave where its particles vibrate in a perpendicular direction to that of the direction of wave.
(c) The sound that the boy made while singing is an example of (transverse, longitudinal) wave.
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16. Name: ____________________ ( )
Class: _____ Date:_____________
Quick Check
Give one example of a longitudinal wave.
Sound wave
3. Label the wave terms – crest, trough, wavelength and amplitude in the displacement-distance graph below of a transverse wave.
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17. Relationship between velocity, frequency and wavelength
Name: ____________________ ( )
Class: _____ Date:_____________
Relationship between velocity, frequency and wavelength
Speed of a wave = frequency of wave X wavelength of the wave
In symbols,
v = f 
v = wave speed/velocity (m/s)
f = frequency (Hz)
 = wavelength (m)
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18. The frequency – period equation
Name: ____________________ ( )
Class: _____ Date:_____________
The frequency – period equation
f = 1/T
Knowing frequency, we can find the period of a wave.
Similarly, if we know the period, we can find the frequency of the wave.
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19. Name: ____________________ ( )
Class: _____ Date:_____________
The Ripple Tank
The ripple tank allows us to observe the behaviour of waves easily.
Basically waves behaves similar to that of light:
Waves reflect
Waves refract
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20. Name: ____________________ ( )
Class: _____ Date:_____________
Measuring wavelength
1 wavelength
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21. Displacement vs distance Graph
Name: ____________________ ( )
Class: _____ Date:_____________
Displacement vs distance Graph
Waves can be plotted on a displacement vs distance graph.
The displacement refers to displacement of particles, while distance refers to the distance of particles from a starting point.
From this graph, we can find:
Wavelength
Amplitude
Distance of particles from a position
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22. Name: ____________________ ( )
Class: _____ Date:_____________
Displacement /m
wavelength
amplitude
Distance/m
amplitude
wavelength
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23. Displacement vs time Graph
Name: ____________________ ( )
Class: _____ Date:_____________
Displacement vs time Graph
Waves can be plotted on a displacement vs time graph.
The displacement refers to displacement of particle just one particle, while time refers to the time of that same particle moves a particular displacement
From this graph, we can find:
Period of wave
Amplitude
From period, we can calculate the frequency of the wave
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24. Name: ____________________ ( )
Class: _____ Date:_____________
Displacement /m
period
amplitude
Time/s
amplitude
period
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25. Eg. Displacement vs time Graph
Name: ____________________ ( )
Class: _____ Date:_____________
Eg. Displacement vs time Graph
A displacement – time graph of a wave with wavelength 0.4m is shown.
Calculate the frequency of the wave.
Period of wave is 0.5 s
So f = 1/T = 1/0.5 = 2 Hz
(b) Calculate the speed of the wave.
Speed = frequency x wavelength = 2 x 0.4
= 0.8m/s
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26. Name: ____________________ ( )
Class: _____ Date:_____________
Displacement /m
0.25
0.5
0.75
1.0
Time/s
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27. Name: ____________________ ( )
Class: _____ Date:_____________
Quick Check
Calculate the wave speed of a wave of frequency 500 Hz and a wavelength of 0.02 m.
v = 500 x 0.02 = 10 m/s
Calculate the wavelength of a wave that has a frequency of 2kHz and speed of 5m/s.
wavelength = v/f = 5/2000 = m
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28. Name: ____________________ ( )
Class: _____ Date:_____________
Quick Check
A wave of speed 330 m/s has a wavelength of 2m.
Calculate the frequency of the wave.
frequency = v/wavelength = 330/2 = 165 Hz
(b) Calculate the period of the wave.
period = 1/f = 1/165 = s
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