Topic: Heat Transfer
For heat transfer across a composite slab with materials having different thermal conductivity, study the following statements.
I. Temperature is continuous always.
II. Temperature gradient is not continuous.
III. Heat flow is not continuous.
- A. Statement I alone is correct
- B. Statement I and II are correct
- C. Statement II alone is correct
- D. All the statements are correct
Answer: B. Statement I and II are correct
Explanation: Temperature profile in any single slab is continuous. The temperature gradient $\frac{dT}{dx} \propto \frac{1}{k}$. Therefore, the temperature gradient is constant in a single slab having constant thermal conductivity. If there are two slabs having different thermal conductivities, they will have different temperature gradients and hence at the interface, the gradient will be non-continuous.