# numerical aperture

> dimensionless number that characterizes the range of angles over which the system can accept or emit light

**Wikidata**: [Q898896](https://www.wikidata.org/wiki/Q898896)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Numerical_aperture)  
**Source**: https://4ort.xyz/entity/numerical-aperture


## References

1. Freebase Data Dumps. 2013
2. [OpenAlex](https://docs.openalex.org/download-snapshot/snapshot-data-format)