Frequency and wavelength depend on propagation speed
For a periodic wave, frequency multiplied by wavelength equals the relevant propagation speed. Frequency alone does not determine wavelength until the medium and wave speed are declared.
CalcOS requires a propagation context in the conversion engine. The page starts with a visible vacuum selection and allows a custom speed supplied by the user.
Vacuum is exact; material speeds are contextual
| Context | Speed treatment | Status |
|---|---|---|
| Electromagnetic wave in vacuum | 299,792,458 m/s | Exact SI defining constant |
| Custom medium | User-entered m/s | Contextual, not independently certified |
| Air, water, glass, cable | No hidden preset | Conditions and frequency may matter |
Phase speed, group speed, and dispersion
Real media can have frequency-dependent propagation and may distinguish phase velocity from group velocity. This converter applies the single speed entered; it does not model dispersion, refractive index, waveguide modes, or pulse propagation.
Frequency-to-frequency and length-to-length conversions
Conversions within the same quantity use exact SI prefixes. A propagation context is still required by the engine so every result carries the same visible assumption contract.
Why zero is rejected
At zero frequency, the reciprocal wavelength relation is unbounded for a positive propagation speed. CalcOS therefore requires finite positive frequency, wavelength, and speed values.
Authoritative references: BIPM definition of the metre, CIPM Recommendation 1 (1997), and NIST Time and Frequency glossary.