Which factor increases the rate of heat transfer?

Which factor increases the rate of heat transfer?

• A. Increase in insulation
• B. Decrease in temperature difference
• C. Increase in surface area
• D. Increase in mass

Answer: (C)

Heat transfer speed rises when there’s more surface area for the heat to move through. In conduction, the rate at which heat flows is proportional to the area: Q/t = k A ΔT / L. This means, keeping the material, thickness, and temperature difference the same, doubling the area doubles how much heat can pass per second. The same idea holds for convection and radiation: more surface area means more heat can be exchanged. Increasing insulation adds resistance and lowers the rate of heat transfer, so it would slow it down. Decreasing the temperature difference reduces the driving force, making heat transfer slower. Mass affects how much energy is needed to change the temperature, not how fast heat moves through a given path, so it doesn’t increase the rate of transfer.

Heat transfer speed rises when there’s more surface area for the heat to move through. In conduction, the rate at which heat flows is proportional to the area: Q/t = k A ΔT / L. This means, keeping the material, thickness, and temperature difference the same, doubling the area doubles how much heat can pass per second. The same idea holds for convection and radiation: more surface area means more heat can be exchanged.

Increasing insulation adds resistance and lowers the rate of heat transfer, so it would slow it down. Decreasing the temperature difference reduces the driving force, making heat transfer slower. Mass affects how much energy is needed to change the temperature, not how fast heat moves through a given path, so it doesn’t increase the rate of transfer.