Not sure if this is the right place to ask this question, but anyways. I'm not very fond of circuits and stuff, but I've got a test question I really need to answer. The question is in the title, possible answer options are:
- Fibrous surface
- Thermal conductivity
- Average density
- Electromagnetic radio waves radiation (as far as I understand, the question suggests that we're speaking about waves produced by the object that we are measuring distance to itself)
Multiple choices are possible. I didn't manage to find an answer on the internet, so I hope someone can help me here.