---
title: "Four metal bars of different materials have identical length \\(L = 0.20\\text{ m}\\) and cross-sectional area \\(A = 1.0 \\times 10^{-3}\\text{ m}^2\\). The thermal conductivities of the metals are given in the table below.  | Metal | Thermal Conductivity \\(k\\text{ (W/(m}\\cdot\\text{K))}\\) | |—|—| | Steel | 50 | | Iron | 80 | | Aluminum | 200 | | Copper | 400 |  One end of the aluminum bar is held at a constant temperature of \\(100^\\circ\\text{C}\\) while the other end is held at \\(20^\\circ\\text{C}\\). Assuming heat flows only along the length of the bar, what is the rate of thermal energy transfer through the aluminum bar?"
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url: "https://nerd-notes.com/ubq/117322/"
date_modified: "2026-08-04T06:51:48+00:00"
---

# Four metal bars of different materials have identical length \(L = 0.20\text{ m}\) and cross-sectional area \(A = 1.0 \times 10^{-3}\text{ m}^2\). The thermal conductivities of the metals are given in the table below.

| Metal | Thermal Conductivity \(k\text{ (W/(m}\cdot\text{K))}\) |
|—|—|
| Steel | 50 |
| Iron | 80 |
| Aluminum | 200 |
| Copper | 400 |

One end of the aluminum bar is held at a constant temperature of \(100^\circ\text{C}\) while the other end is held at \(20^\circ\text{C}\). Assuming heat flows only along the length of the bar, what is the rate of thermal energy transfer through the aluminum bar?

Four metal bars of different materials have identical length \(L = 0.20\text{ m}\) and cross-sectional area \(A = 1.0 \times 10^{-3}\text{ m}^2\). The thermal conductivities of the metals are given in the table below.

| Metal | Thermal Conductivity \(k\text{ (W/(m}\cdot\text{K))}\) |
|---|---|
| Steel | 50 |
| Iron | 80 |
| Aluminum | 200 |
| Copper | 400 |

One end of the aluminum bar is held at a constant temperature of \(100^\circ\text{C}\) while the other end is held at \(20^\circ\text{C}\). Assuming heat flows only along the length of the bar, what is the rate of thermal energy transfer through the aluminum bar?

- **A.** \(20\text{ J/s}\)
- **B.** \(80\text{ J/s}\)
- **C.** \(160\text{ J/s}\)
- **D.** \(400\text{ J/s}\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/117322/*