# speed of light in a medium

> phase speed of an electromagnetic wave in a medium

**Wikidata**: [Q9092845](https://www.wikidata.org/wiki/Q9092845)  
**Source**: https://4ort.xyz/entity/speed-of-light-in-a-medium


## References

1. ISO 80000-7:2019 Quantities and units — Part 7: Light and radiation