[Image Question] The temperature profile between two metal wall joined together is shown in Fig. From the figure it can be concluded that
- A. Heat flows from A to B
- B. Heat flows from B to A
- C. Heat is generated at the interface
- D. A is bad conductor of heat
Answer: D. A is bad conductor of heat
Explanation: The temperature gradient in A is steeper than in B. Since $q = -kA(dT/dx)$, for the same heat flux, a steeper gradient implies lower thermal conductivity (k). Thus A is a worse conductor than B. Heat flows from high to low temp (A to B).