GED Science TestPhysical ScienceMedium
An engineer is designing a heat exchange system. They want to transfer heat efficiently from a hot liquid to a cooler liquid without the two liquids mixing. Which of the following materials would be the most suitable choice for the barrier separating the two liquids?
- ACopper, because it is a good thermal conductor.
- BGlass, because it is transparent.
- CWood, because it is readily available.
- DPlastic, because it is lightweight.
Show answer & explanationAnswer & explanation
Correct answer: A. Copper, because it is a good thermal conductor.
For efficient heat transfer without mixing, a material with high thermal conductivity is required. Copper is an excellent thermal conductor, meaning it transfers heat very effectively.
Why the other options are wrong
- B. Transparency is not relevant for heat transfer; glass is a moderate thermal conductor.
- C. Wood is a poor thermal conductor (an insulator), which would hinder heat transfer.
- D. Lightweight property is not the primary concern for efficient heat transfer; plastic is generally a poor thermal conductor.
Thermal Conductivity
A measure of a material's ability to transfer heat.
- High thermal conductivity means efficient heat transfer.
- Low thermal conductivity indicates a good insulator.
- Metals (like copper, aluminum) are excellent conductors.
- Gases, plastics, and wood are generally poor conductors (good insulators).
Memory trick: Conductors Carry, Insulators Ignore.