Free · Acoustic waves calculators 🔊

Wave Speed, Period & Spatial Frequency

Solve the relationship between wave speed, period, frequency, wavelength and ordinary spatial frequency.

  • Formula & worked example
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Calculator inputs

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

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Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Formula and method

A wave with frequency 5 Hz and wavelength 2 m travels at 10 m/s. Its period is 0.2 s and its ordinary wavenumber is 0.5 m⁻¹.

v = fλ; period = 1/f; ordinary wavenumber = 1/λ

Worked example

Enter these known values and leave the other values blank.

Wave frequency
5 Hz
Wavelength
2 m
Wave period
0.2 sec
Ordinary wavenumber (cycles per length)
0.5 1/ m
Phase speed
10 m/s

Assumptions and limitations

  • All wave quantities here are positive magnitudes. Speed means phase speed, not particle speed or necessarily group velocity.
  • Use quantities for the same periodic wave in the same medium. Dispersion and changes in the medium are not modeled.
  • Ordinary wavenumber is cycles per length, not the angular value 2π/λ. The tool does not select or infer a material.
  • Period is the time for one complete cycle. Entering a period can replace entering frequency.

Common questions

Does wavenumber mean 1/λ or 2π/λ?

Both conventions appear in scientific work. The ordinary wavenumber here is 1/λ, in cycles per length. Angular wavenumber is 2π/λ, in radians per length. Always check the convention used by your formula.

Can I use period and wavelength instead of frequency?

Yes. Frequency is the reciprocal of period, so phase speed is wavelength divided by period.

References

The calculation equations, inverse formulas, units, and input rules were imported from this source. Bookify provides the interface and equation solver.

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