Which statement about radiation in everyday heating contexts is true?

Which statement about radiation in everyday heating contexts is true?

• A. Radiation can transfer heat through empty space.
• B. Radiation requires a medium to travel.
• C. Radiation only occurs in solids.
• D. Radiation cannot transfer heat from a flame.

Answer: (A)

Heat transfer by radiation moves energy through electromagnetic waves and does not need any material to travel through; it can cross empty space. This is why you can feel warmth from a fire, a heater, or the sun even when there’s no air in between. The strength of radiant heat depends on how hot the source is, how far away you are, and how well the surface emits infrared energy. A flame can warm objects across a room by radiation. Conduction needs direct contact with a substance, and convection requires a moving fluid, so those modes need a medium. Radiation isn’t limited to solids; liquids and gases also emit and absorb radiant energy.

Heat transfer by radiation moves energy through electromagnetic waves and does not need any material to travel through; it can cross empty space. This is why you can feel warmth from a fire, a heater, or the sun even when there’s no air in between. The strength of radiant heat depends on how hot the source is, how far away you are, and how well the surface emits infrared energy. A flame can warm objects across a room by radiation. Conduction needs direct contact with a substance, and convection requires a moving fluid, so those modes need a medium. Radiation isn’t limited to solids; liquids and gases also emit and absorb radiant energy.