A brass rod with a length of 20.0 cm is placed end to end with an aluminum rod with a length of 20.0 cm and this system is placed between a hot temperature of 100$^{\circ}$C and a cold temperature of 10.0$^{\circ}$C.The coefficient of thermal conductivities of the brass and the aluminum are 100 W/m C and 230 W/m $^{\circ}$C respectively.The rods have the same cross sectional area of 25.0 cm².What is the heat flow from the hot temperature to the cold temperature?

Question

Quizplus · Accepted Answer

The heat flow is given by the equation:Q = k * A * (T2 - T1) / Lwhere:Q is the heat flow in wattsk is the thermal conductivity in W/m CA is the cross-sectional area in m2T2 is the hot temperature in CT1 is the cold temperature in CL is the length in mFor the brass rod, we have:Q1 = k1 * A * (T2 - T1) / L1Q1 = 100 W/m C * 25.0 cm2 * (100 C - 10 C) / 20.0 cmQ1 = 450 WFor the aluminum rod, we have:Q2 = k2 * A * (T2 - T1) / L2Q2 = 230 W/m C * 25.0 cm2 * (100 C - 10 C) / 20.0 cmQ2 = 1035 WThe total heat flow is the sum of the heat flows through the two rods:Q = Q1 + Q2Q = 450 W + 1035 WQ = 1485 WTherefore, the heat flow from the hot temperature to the cold temperature is 1485 W.

A Brass Rod with a Length of 20 ∘^{\circ}∘ C and a Cold Temperature of 10

A Brass Rod with a Length of 20 $^{\circ}$ C and a Cold Temperature of 10