Question

Which of these best describes heat transfer through conduction? A) Heat transfer as electrons are excited in atoms. B) Heat transfer by the emission of pure energy waves. C) Heat transfer by a liquid or gas flowing over an object. Eliminate D) Heat transfer by molecules colliding with adjacent molecules.

Answer 1

Answer: D) Heat transfer by molecules colliding with adjacent molecules.

Explanation:

The heat transfer is achieved by three modes:

a. Conduction: This type of heat transfer happens when there is direct contact between two objects. In conduction, heat is transferred by molecules bumping into each other.

b. Convection: This type of heat transfer happens when there is a movement of fluid (liquid or gas).

The hot liquid rises up due to its low density and the cold liquid sinks thus generating convection currents.

c. Radiation: This type of heat transfer happens when there is direct transfer of electromagnetic energy through space.

Answer 2

I'd go for D here. It also fits in with the idea of thermal expansion - as something is heated up, molecules vibrate and maybe collide. they vibrate with bigger amplitudes, so taking up more space, so expanding. maybe