General Wave Properties
Waves A wave transfers energy from one place to another without the
transfer of particles in the medium. Rather, individual particles vibrate
(oscillate) about fixed positions instead.
Wave motion can be easily exemplified by vibrations in:
Ropes
Springs
Water
Types of waves
There are two types of waves namely longitudinal waves and transverse
waves
In a longitudinal wave (such as sound), the particles vibrate parallel to
the direction of the wave. This leads to compressions (particles are
closer together than normal) and rarefactions (particles are further apart
than normal)
In a transverse wave (such as light), particles vibrate perpendicular to
the direction of the wave. This leads to a series of peaks (particles are
higher than normal) and troughs (particles are lower than normal).
Some important terms that you must be aware of are:
1. Wavelength is the distance between adjacent particles that are at
the same point in their vibration
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In a transverse wave, it is the distance between two adjacent peaks
or troughs
In a longitudinal wave, it is the distance between two adjacent
compressions or rarefactions
2.Amplitude is the maximum displacement of particles from rest
position
3. Velocity of the wave is the distance traveled per second, and is
measured in m/s
4.Frequency of the wave is the number of complete waves passing a
point per second, and is measured in hertz (Hz)
5.Wavefronts can be represented as lines which are always
perpendicular to the direction of wave travel. The distance between
one wavefront to the next is the wavelength
6.Combining velocity, frequency and wavelength produces this wave
equation:
Reflection, refraction and diffraction
Reflection
When waves hit a plane surface, it will reflect off it. The frequency,
speed or wavelength of the wave remains unchanged in reflection.
Refraction
A wave will become refracted if it travels from one medium to another
medium with a different density. The speed of the wave changes, and
that causes a change in direction of the wave.
Water travels more slowly in shallow water compared to deep
water.
The wavelength decreases and the direction shifts as the waves hit the
more shallow side but frequency remains the same.
Diffraction
Diffraction is the process by which waves spread out as a result of
passing through a narrow gap or across an edge of an object.
As water waves pass through the gap, you can observe the spreading of
the new wavefronts:
The extent of diffraction is dependent on the size of the gap in
comparison to the wavelength of the wave.
Diffraction can also occur as waves hit the edge of a barrier.
The longer the wavelength the greater the diffraction that occurs.