| Clue | Source | Date |
|---|---|---|
| Quantum light particles | Universal | 29 Oct 2024 |
| Electromagnetic particles | ||
| Light particles | Universal | 13 Jan 2024 |
| Particles of light | Newsday | 12 Feb 2023 |
| Electromagnetic energy units | Universal | 20 Feb 2016 |
| Gamma rays, essentially | Wall Street Journal | 30 Jan 2016 |
| Light quanta | ||
| Radiation particles | ||
| Light quanta | ||
| Light intensity units | ||
| Electromagnetic energy units | ||
| Particles in physics |