A painted rectangular sheet of area is found experimentally to radiate when its…
PHYSICS · Subjective · CBSE · Physics · Thermal Properties of Matter · Thermal Properties of Matter
Problem
A painted rectangular sheet of area 0.15m2 is found experimentally to radiate 540W when its temperature is 600K. The surroundings are at a much lower temperature so that any absorption of radiation by the sheet may be neglected.
(i) Calculate the emissivity of the painted surface. Take the Stefan constant to be 5.67×10−8W m−2K−4.
(ii) Keeping the emissivity the same, estimate the radiant power the sheet would emit when its temperature is raised to 900K.