Answer the following questions related to thermal radiation from surfaces:
PHYSICS · Multi-part · CBSE · Physics · Thermal Properties of Matter · Thermal Properties of Matter
Problem
Answer the following questions related to thermal radiation from surfaces:
(i) Define total emissive power of a surface and state how it varies with absolute temperature for an ideal absorber.
(ii) Explain briefly why the rate at which a body radiates energy increases very rapidly at high temperatures.
(iii) Two identical metal plates are maintained at the same temperature in identical surroundings. Plate A is highly polished with emissivity 0.10 whereas plate B is rough with emissivity 0.80. Compare qualitatively the total power radiated by the two plates and justify your answer.
(iv) If the absolute temperature of an ideal absorber is tripled, by what factor does its total power radiated per unit area change? Show your reasoning clearly.