Heat transfer via electromagnetic waves in a vacuum

Steps:

• Identify heat transfer processes: conduction (direct contact), convection (fluid motion), evaporation (phase change), radiation (electromagnetic waves).
• Note vacuum lacks matter, so processes needing particles or fluids can't occur.
• Eliminate options requiring medium: conduction needs solids/liquids, convection needs fluids, evaporation needs liquid phase.
• Select radiation, as it propagates through empty space without medium.

Why D is correct:

• Radiation transfers heat as electromagnetic waves, following the Stefan-Boltzmann law (energy ∝ T⁴), independent of medium.

Why the others are wrong:

• A: Conduction requires direct particle contact, impossible in vacuum.
• B: Convection relies on fluid movement to carry heat, absent in vacuum.
• C: Evaporation needs a liquid substance, which can't exist or transfer heat in vacuum without it.

Final answer: D