Radiation in energy transfer refers to?

• A. The transfer of energy through electromagnetic waves emitted by the higher energy object and absorbed by the lower energy object
• B. The transfer of heat by the movement of gas or a liquid due to pressure difference
• C. The transfer of energy that occurs when objects are in direct contact and electrons transfer heat
• D. The conversion of heat to electricity

Answer: (A)

Radiation is energy transfer through electromagnetic waves emitted by a hotter object and absorbed by a cooler one. It can happen through empty space, so no medium is required (think of the Sun warming Earth). The rate depends on temperature, surface area, and emissivity. This makes radiation different from conduction, which needs direct contact for energy to move via molecules, and convection, which relies on fluid movement driven by density and temperature differences. Radiation isn’t about converting heat to electricity by itself; that’s a separate energy-conversion process using devices to harvest heat.