| Answer | Crossword Clue |
|---|---|
| RHO | Reflectance symbol |
| reflectometer | instrument for measuring reflectance of radiant energy |
| reflectometers | REFLECTOMETER, instrument for measuring reflectance of radiant energy |
| reflectances | REFLECTANCE, the ratio of reflected radiation to incident radiation |
| reflectivity | The property of reflecting light or radiation, esp. reflectance as measured independently of the thickness of a material |
