What type of heat transfer requires physical contact between materials?

What type of heat transfer requires physical contact between materials?

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

Answer: (B)

The correct answer is conduction, which refers to the transfer of heat that occurs through direct physical contact between materials. In this process, heat moves from the hotter object to the cooler object through the collision of molecules. For example, when you touch a hot pan, the heat from the pan transfers to your hand through conduction, resulting in a sensation of warmth or even a burn if the contact is prolonged. In contrast, convection involves the transfer of heat through the movement of fluids (liquids or gases) and does not require direct contact between the heat source and the fluid. Radiation, on the other hand, is the transfer of heat in the form of electromagnetic waves and can occur in a vacuum, without any physical contact. Evaporation is a process where liquid turns into vapor and is not directly related to heat transfer between materials in contact. Understanding these differences is essential in recognizing how heat is transferred in various situations.

The correct answer is conduction, which refers to the transfer of heat that occurs through direct physical contact between materials. In this process, heat moves from the hotter object to the cooler object through the collision of molecules. For example, when you touch a hot pan, the heat from the pan transfers to your hand through conduction, resulting in a sensation of warmth or even a burn if the contact is prolonged.

In contrast, convection involves the transfer of heat through the movement of fluids (liquids or gases) and does not require direct contact between the heat source and the fluid. Radiation, on the other hand, is the transfer of heat in the form of electromagnetic waves and can occur in a vacuum, without any physical contact. Evaporation is a process where liquid turns into vapor and is not directly related to heat transfer between materials in contact. Understanding these differences is essential in recognizing how heat is transferred in various situations.