Question

which two conditions must exist in order for radiation to occur? the presence of a solid, liquid, or gas and a temperature difference direct contact of molecules and the presence of a solid, liquid, or gas the presence of electromagnetic waves and direct contact of molecules a temperature difference and the presence of electromagnetic waves

Explanation:

Radiation is heat - transfer by electromagnetic waves. It occurs when there is a temperature difference and electromagnetic waves are emitted and absorbed to transfer heat between objects.

Answer:

A temperature difference and the presence of electromagnetic waves