Which of the following is an example of radiation?

Radiation is a method of heat transfer that occurs through electromagnetic waves and does not require a medium (like air or water) to travel through. The most fitting example of radiation among the given choices is the nuclear bomb, which releases energy in the form of heat and radiation, including gamma rays, as a result of nuclear reactions. This process demonstrates the release and transfer of energy through radiation.

In contrast, conduction and convection are both methods of heat transfer that require the presence of matter. Conduction refers to direct heat transfer through a material, while convection involves the movement of fluids. X-ray diffraction, while related to the wave nature of X-rays, primarily deals with the interaction of X-rays with matter, rather than being a direct example of radiation in the context of heat transfer.