3 a) units b) properties of waves Flashcards
3.1 use the following units: degree (°), hertz (Hz), metre (m), metre/second (m/s), second (s).
Unit of an angle: degree (o)
Unit of frequency: hertz (Hz)
Unit of distance or wavelength: metre (m)
Unit of speed/velocity: metre/second (m/s)
Unit of time-period: second (s)
3.2 understand the difference between longitudinal and transverse waves and describe experiments to show longitudinal and transverse waves in, for example, ropes, springs and water
Transverse waves: A transverse wave is one that vibrates or oscillates, at right angles to the direction in which the energy or wave is moving. Example of transverse waves include light waves and waves travelling on the surface of water.
http://www.shawonnotes.com/IGCSE_Physics/physics_images/transverse-wave.jpg
Longitudinal waves: A longitudinal wave is one in which the vibrations or oscillations are along the direction in which the energy or wave is moving. Examples of longitudinal waves include sound waves.
http://www.shawonnotes.com/IGCSE_Physics/physics_images/Longitudinal-Wave-vibration.png
Transverse wave don’t need medium to move. Longitudinal wave needs medium to move.
3.2 - experiments to show longitudinal and transverse waves
Transverse:
http://www.shawonnotes.com/IGCSE_Physics/physics_images/experiment-transverse-spring.jpg
If you waggle on end of a slinky spring from side to side you will see waves travelling through it. The energy carried by these waves moves along the slinky from one end to the other, but if you look closely you can see that the coils of the slinky are vibrating across the direction in which the energy is moving. This is an example of transverse wave.
Longitudinal:
http://www.shawonnotes.com/IGCSE_Physics/physics_images/experiment-longitudinal-spring.jpg
If you push and pull the end of a slinky in a direction parallel to its axis, you can see energy travelling along it. This time however the coil of the slinky are vibrating in direction that are along its length. This is an example of longitudinal wave.
3.3 define amplitude, frequency, wavelength and period of a wave
Amplitude: The maximum movement of particles from their resting position by a wave is calleds its amplitude (A).
Wavelength: The distance between a particular point on a wave and the same point on the next wave (for example, from crest to crest) is called the wavelength (λ).
Frequency: The number of waves produced each second by a source, or the number passing a particular point each second is called frequency ( f).
Period: The period of a wave is the time for one complete cycle of the waveform.
http://www.shawonnotes.com/IGCSE_Physics/physics_images/amplitude-wavelength.jpg
3.4 understand that waves transfer energy and information without transferring matter
Waves are means of transferring energy and information from place to place. These transfers take place with no matter being transferred. Mobile phones, satellites etc. rely on waves.
Example: If you drop a large stone into a pond, waves will be produced. The waves spread out from the point of impact, carrying to all parts of the pond. But the water in the pond does not move from the centre to the edges.
3.5 know and use the relationship between the speed, frequency and wavelength of a wave:
wave speed = frequency × wavelength
v = f× λ
3.6 use the relationship between frequency and time period
frequency = 1 / time-period f = 1/T
3.7 use the above relationships in different contexts including sound waves and electromagnetic waves
As all wave share properties the above relations can be used for any type of wave.