Four rods with different radii r and length l are connected to two reservoirs at different temperature. Which one of them will conduct most heat?
- A. r = 2 cm & l = 2 m
- B. r = 1 cm & l = 1 m
- C. r = 2 cm & l = 1/2 m
- D. r = 1/2 cm & l = 1/2 m
Answer: C. r = 2 cm & l = 1/2 m
Explanation: Heat rate $Q \propto Area/Length \propto r²/l$. Maximizing this ratio gives the answer.