Question

What process transfers heat by electromagnetic waves?

Answer 1

I would say the processo of Radiation.

Explanation:

Thermal radiation is energy transfer by the emission of electromagnetic waves which carry energy away from the emitting object. For ordinary temperatures (less than red hot"), the radiation is in the infrared region of the electromagnetic spectrum.
For reference have a look at:
http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/stefan.html#c2