Topic: Heat Transfer
If the temperature of a solid surface changes from 27 °C to 81 °C, then its emissive power changes in the ratio of nearly
- A. 81
- B. 9
- C. 1.49
- D. 1.94
Answer: D. 1.94
Explanation: Emissive Power (E) is proportional to T^4. E2/E1 = (T2/T1)^4 = ((81+273)/(27+273))^4 = (354/300)^4 = 1.938, which is approximately 1.94.