Topic: Heat Transfer
A flat plate of length 1 m and width 50 cm is placed in an air stream at 30°C blowing parallel to it. The convective heat transfer co-efficient is 30 W/(m²K). The heat transfer if the plate is maintained at a temperature of 400°C is
- A. 5.55 kW
- B. 4.05 kW
- C. 55.5 kW
- D. 6 kW
Answer: A. 5.55 kW
Explanation: The surface area of the plate is $A = L \times w = 1 \text{ m} \times 0.50 \text{ m} = 0.50 \text{ m}^2$. The convective heat transfer is determined using Newton's law of cooling: $Q = hA\Delta T$. Substituting the given values provides $Q = 30 \times 0.50 \times (400 - 30) = 15 \times 370 = 5550 \text{ W}$, which equals 5.55 kW.