Cheatography
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6.1 Waves in air, fluids and solids
6.2 Electromagnetic waves
6.3 Black body radiation
This is a draft cheat sheet. It is a work in progress and is not finished yet.
6.1.1 Transverse and Longitudinal Waves
· Waves are either transverse or longitudinal.
· Waves transfer energy from one place to another without transferring matter. |
transverse |
- the oscillations are perpendicular to the direction of energy transfer
- have crests (peaks) and troughs ; e.g. light waves, EM waves, radio waves |
longitudinal |
- the oscillations are parallel to the direction of energy transfer
- have compressions and rarefactions ; e.g. sound waves, seismic P waves |
For any wave, the wave moves and not the medium it passes through
-> i.e. ripples in water move, but the water doesn't move with it
-> i.e. sounds in air moves, but the air doesn't move with it |
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6.1.2 Properties of Waves
amplitude
wavelength
frequency
period
wave speed |
- the maximum displacement of a point on a wave away from its undisturbed position
- the distance from a point on one wave to the equivalent point on the adjacent wave
- the number of waves passing a point each second
- the time it takes for one entire oscillation of a wave
- the speed at which the energy is transferred (or the wave moves) through the medium |
t = 1 / f
v = fλ |
time period (s) = 1 / frequency (Hz)
velocity (m/s) = frequency (Hz) x wavelength (m) |
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