A body at
1100°C
in black surroundings at
550°C
has an emissivity of 0.4 at
1100°C
and 0.7 at
550°C
. Calculate the rate of heat loss by radiation per square metre.
a) when the body is assumed gray
b) w
hen the body is not gray
c) What is the error in assuming a gray body? Assuming that the absorptivity is independent of the
surface temperature.