Question

which of the following is the best description of radiation?
a. heat transfer in a gas or liquid by the circulation of currents from one region to another
b. the process by which a liquid is converted to its vapor phase by heating the liquid
c. the emission of energy in the form of rays or waves
d. the transmission of heat through a medium without the motion of the medium

Explanation:

• Option A describes convection (heat transfer via fluid currents), not radiation.
• Option B is evaporation (liquid to vapor), unrelated to radiation.
• Option C correctly defines radiation as energy emission in rays/waves (e.g., light, infrared).
• Option D describes conduction (heat transfer through medium without bulk motion), not radiation.

Answer:

C. the emission of energy in the form of rays or waves