| Answer | Crossword Clue |
|---|---|
| DIODE | Tube that may be light-emitting |
| complementarity | The concept that two contrasted theories, such as the wave and particle theories of light, may be able to explain a set of phenomena, although each separately only accounts for some aspects |
| coude | of, relating to, or being a telescope constructed so that the light is reflected along the polar axis to come to a focus at a point where the holder for a photographic plate or a spectrograph may be mounted |
