Which statement defines radiation?

Which statement defines radiation?

• A. The transfer of energy by electromagnetic waves
• B. The transfer of energy through direct contact
• C. Conduction through a fluid
• D. Increase in kinetic energy due to motion

Answer: (C)

Radiation is the transfer of energy by electromagnetic waves. This means heat can move from a hot object to a cooler one without needing a medium—think sunlight warming the Earth even through the vacuum of space. Conduction transfers energy by direct contact and particle collisions, in solids or fluids. An increase in kinetic energy due to motion describes energy appearing as motion, not the mechanism by which heat travels. So the defining statement is energy transfer through electromagnetic waves.

Radiation is the transfer of energy by electromagnetic waves. This means heat can move from a hot object to a cooler one without needing a medium—think sunlight warming the Earth even through the vacuum of space. Conduction transfers energy by direct contact and particle collisions, in solids or fluids. An increase in kinetic energy due to motion describes energy appearing as motion, not the mechanism by which heat travels. So the defining statement is energy transfer through electromagnetic waves.