Recognised as Physical constant
Speed of light in vacuum
- c
- Exact by definition
- universal
Speed of light in vacuum (c) is 299,792,458 m/s. Exact by definition: since 1983 the metre has been defined in terms of it. Values follow CODATA 2018 (2019 SI redefinition).
Value
Value299,792,458 m/s
Scientific notation2.99792458 × 10^8 m/s
Unitm/s
Symbolc
ExactnessExact by definitionExact by definition: since 1983 the metre has been defined in terms of it.
Reciprocal3.335640952 × 10^-9
Order of magnitude10^8
Multiples
× 25.99584916 × 10^8
× 102.99792458 × 10^9
× 1002.99792458 × 10^10
× 1,0002.99792458 × 10^11
× 0.51.49896229 × 10^8
× 0.12.99792458 × 10^7
Provenance
DatasetCODATA 2018 (2019 SI redefinition)
Categoryuniversal
Why it mattersExact by definition: since 1983 the metre has been defined in terms of it.
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