Which statement about heat transfer by conduction is true?

• A. Heat passes through a vacuum.
• B. Heat transfer by movement of gas or liquid due to pressure difference.
• C. Heat transfer by electromagnetic waves.
• D. Heat passes through a solid material.

Answer: (D)

Conduction relies on direct energy exchange between particles in a material. In solids, particles are tightly packed, so they can transfer kinetic energy efficiently from a hotter region to a cooler region through collisions and vibrations. In metals, free electrons move rapidly and carry energy quickly, boosting conduction.

Heat passing through a vacuum isn’t possible by conduction because there’s no material to transfer energy through. Convection involves the bulk movement of a fluid driven by density differences, not just contact between neighboring particles. Radiation transfers heat via electromagnetic waves and can occur through empty space, without any medium.

So saying that heat passes through a solid material is the accurate description of conduction. It highlights how energy moves through matter by contact and internal interactions.