A Brass Rod with a Length Of $10.0 \mathrm{~cm}$ Is Placed End to End with an Aluminum Rod with Placed

A brass rod with a length of $10.0 \mathrm{~cm}$ is placed end to end with an aluminum rod with a length of $30.0 \mathrm{~cm}$ , and this system is placed between a hot temperature of $100^{\circ} \mathrm{C}$ and a cold temperature of $10.0^{\circ} \mathrm{C}$ . The thermal conductivities of the brass and the aluminum are $100 \mathrm{~W} / \mathrm{m}^{\circ} \mathrm{C}$ and $230 \mathrm{~W} / \mathrm{m}^{\circ} \mathrm{C}$ , respectively. The rods have the same cross-sectional area of $20.0 \mathrm{~cm}^{2}$ . What is the heat flow from the hot temperature to the cold temperature?

A) $55.3 \mathrm{~W}$
B) $65.3 \mathrm{~W}$
C) $78.1 \mathrm{~W}$
D) $70.3 \mathrm{~W}$
E) $85.3 \mathrm{~W}$