104. In the diagram, a system of two metals of equal lengths and of sa...
Understanding the Heat Transfer in the SystemIn this scenario, we have two metals connected in series, one with thermal conductivity K and the other with 2K. The temperature differential between the furnace (300°C) and the ice box (0°C) creates a heat flow through both metals.
Heat Transfer Basics- The heat transfer (Q) through a material is governed by Fourier's law:
Q = k * A * (ΔT/L)
where k is the thermal conductivity, A is the cross-sectional area, ΔT is the temperature difference, and L is the length of the material.
Temperature Gradient- The system's steady-state temperature gradient will depend on the thermal resistances of both metals:
R1 = L/(K * A) for Metal I
R2 = L/(2K * A) for Metal II
- The total thermal resistance (R_total) is:
R_total = R1 + R2 = (L/(K * A)) + (L/(2K * A))
Calculating the Temperature at the Junction- The effective thermal resistance indicates that more heat will flow through Metal II due to its higher conductivity. The temperature at the junction (T_j) between the two metals can be found using the heat balance:
Q = (T_furnace - T_j)/R1 = (T_j - T_icebox)/R2
- By solving these equations, you can derive the temperature at the junction, which will be closer to the furnace temperature due to the higher conductivity of Metal II.
Conclusion- The final temperature at the junction will be influenced heavily by the thermal conductivities of the metals, emphasizing the role of material properties in thermal systems.