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MUS - Progress Check - Coggle Diagram
MUS - Progress Check
L1 - Describing Waves
Longitudinal waves oscillate parallel to the direction of energy transfer; they require a medium through which to propagate and examples include: seismic waves(p) and sound waves.
Transverse waves oscillate perpendicular to the direction of energy transfer. They are capable of propagating through a vacuum and examples include EM waves, seismic waves(s) and water ripples.
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The wavelength of a wave is the distance from a point on a wave to the same point on the adjacent wave.
The frequency of a wave is the number of complete waves that pass a point per second or the number of complete waves produced by a source each second. The human hearing range is between 20 and 20,000Hz.
The period of a wave is the time it takes for a full wave to complete; it can be calculated through the reciprocal of the frequency.
L6 - Lasers
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When an atom absorbs a photon of an energy equal to one of the discrete energy levels. The this can cause electron excitation, resulting in an electron moving up an energy level. This state is unstable and the electron will attempt to return to its ground state.
The energy of an individual photon is related to the frequency of the light through the equation E = hf.
De-excitation causes the electron to move to its ground state (perhaps in jumps). This results in the atom emitting energy (in the form of a photon) equal to the energy difference between the energy levels jumped between.
Lasers have a single frequency. All light is emitted in a narrow beam and the light is coherent (in phase).
*Lasers:
1) An electrical current excites a number of atoms, this produces de-excitation (and so photon emission).
2) This photon will hit another excited atom
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L5 - Standing Waves
A standing wave will be formed when a progressive wave interferes with its reflected counterpart (reflected at a boundary); this results in the waves superimposing, causing interference. Points of no displacement are caused by destructive interference when the waves are anti-phase. Points of maximum displacement are caused by constructive interference when the waves are in phase.
The simplest standing wave that can be formed for a string is known as the fundamental frequency. Harmonics of a larger frequency are known as overtones.
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L4 - Superposition
Superposition will occur when two or more waves overlap in space. Giving a relative disturbance equal to the algebraic sum of the individual disturbances.
For coherent waves, the phase difference between the waves at any point is constant and can vary, are of the same frequency and are of the same amplitude.