Which statement describes radiation?

Which statement describes radiation?

• A. Radiation energy is energy that travels in light waves
• B. Heat is energy transferred between substances that have different temperatures
• C. Conduction is energy transferred through direct contact of molecules
• D. Convection is the rising warm mass and sinking cool mass in a fluid

Answer: (A)

Radiation is the transfer of energy through space by electromagnetic waves. It doesn’t need a medium, so heat can move from a hot object to another place without touching it or without any air or matter in between. Saying that radiation energy travels in light waves captures this idea: energy is carried by waves, with light (an example of electromagnetic waves) being a familiar form. You can feel radiation as warmth from the Sun or a campfire without touching the source. The other statements describe conduction (energy transfer by direct contact of molecules) and convection (energy transfer by the movement of a fluid), or simply define heat transfer in general, which are different mechanisms from radiation.

Radiation is the transfer of energy through space by electromagnetic waves. It doesn’t need a medium, so heat can move from a hot object to another place without touching it or without any air or matter in between. Saying that radiation energy travels in light waves captures this idea: energy is carried by waves, with light (an example of electromagnetic waves) being a familiar form. You can feel radiation as warmth from the Sun or a campfire without touching the source. The other statements describe conduction (energy transfer by direct contact of molecules) and convection (energy transfer by the movement of a fluid), or simply define heat transfer in general, which are different mechanisms from radiation.