Section 13
Waves
The speed of a wave is the product of wavelength and frequency.
The period of a wave is the reciprocal of its frequency.
The wave number is 2π divided by the wavelength.
Also
The angular frequency of a wave is 2π times the frequency; the speed is ω/k.
For propagation toward
For propagation toward
Harmonic wave propagating in one direction or the other, with wave number k and angular frequency ω.
where
Speed of a transverse wave on a string, determined by the tension and the linear density.
Allowed lengths
Natural frequencies of a string fixed at both ends, integer multiples of v/(2L).
The total displacement is the sum of the displacements of the individual waves.
Constructive
Destructive
Constructive or destructive interference depends on the path difference in multiples of the wavelength.
For an isotropic point source
Intensity is power per unit area; for a spherical point source, P/(4πr²).