A steel rod is initially very cold. If it is placed close to a fire, which method of heat transfer will primarily cause the rod to become warmer?

• A. Conduction
• B. Radiation
• C. Evaporation
• D. Convection

Answer: (A)

Verified step by step guidance

1. Identify the three main methods of heat transfer: conduction, convection, and radiation. Each method involves a different mechanism for transferring thermal energy.
2. Understand that conduction is the transfer of heat through direct contact between molecules, where kinetic energy is passed from one particle to another without the particles themselves moving significantly.
3. Recognize that convection involves the movement of fluid (liquid or gas) carrying heat with it, which is not the primary mechanism when a solid rod is heated by a nearby fire without fluid flow inside the rod.
4. Know that radiation is the transfer of heat through electromagnetic waves, which can occur without a medium, but in this scenario, the rod warms primarily due to direct contact with hot air or surfaces.
5. Since the steel rod is a solid and heat is transferred through direct molecular interaction within the rod, the primary method of heat transfer causing the rod to warm is conduction.