What type of electromagnetic energy is invisible to the human eye?
Any electromagnetic energy that is smaller than 400 nanometres or larger than 700 nanometres.
The electromagnetic spectrum is vast, ranging from the smallest Gamma waves at
Just above our view is the infra-red section, and just under is ultra-violet. Why our eyes only evolved to see such a small part of the spectrum, I don't know. But thanks to this, Any electromagnetic energy that is smaller than 400 nanometers or larger than 700 nanometers is invisible to the human eye.
I hope that helped!