Yes you can, with using scientific experiment.
Ask a question -- Do background Research -- Construct a Hypothesis --Test with an Experiment -- Procedure working? -- Yes or no? -- Analyze Data and Draw Conclusions
With an experiment you can discover if its correct or not.
Hope this helps ! <3
Answer:
Accelerating charges.
Explanation:
Electromagnetic waves are waves produced by the vibration of both electrical and magnetic fields.
This interaction produces an energy source that does not require any medium to propagate.
To produce electromagnetic waves, electric and magnetic fields must be vibrating.
An electric charge produced when vibrating under voltage will produce electromagnetic waves. This is the same for all sources of these waves.
The sun produces electromagnetic waves. A lot of human activities also does this.
The answer would be "mechanical". Hope I helped. :)