Answer:
Heating of the liquid water in a microwave.
Explanation:
Radiation is a form of heat transfer process that does not require a material medium rather it travels through space or vacuum in the form of electromagnetic waves or radiation. Heat transfer by radiation occurs in the form of microwaves, infrared radiation, visible light, or another form of electromagnetic radiation is emitted or absorbed. Some common examples of heat transfer by radiation is the warming of the Earth by the Sun, the warmth one experiences while sitting by the campfire, or the heating up of foods in a microwave.
Black bodies or surfaces are good absorbers as well as emitters of radiation. On the other shiny or white surfaces are poor radiators of heat.
From the above discussion on radiation, it can be seen that when the chemist takes the liquid and heats it in a microwave, the heat absorbed by the liquid to change to gaseous state is transferred through radiation.
