It's hard to believe, for that matter.Maybe, but if you know that different dielectrics have an effect on an alternating current's presentation.
You may be aware that a rising and falling electrical field also creates a magnetic field, and that field is outside the dielectric (insulator).
This is part of what accounts for a transformer, the magnetic field is mathematically connected to the rising and falling alternating current.
The other important use of technology is inductance from the secondary windings where depending on winding ratios voltage and amperage can be transferred without a conductive material.
https://www.youtube.com/watch?v=vh_aCAHThTQ