Question

A metal piece loses 200 joules heat per second by radiation when its temperature is 1400 k and the temperature of the surroundings is 300k. Calculate the rate of loss of heat when the temperature of the metal piece is 800k

Answer 1

its so hard i cant answer it

Answer 2

E1\E2=sigma(T1^4-T2^4)/sigma(T3^4-T4^4)

200/x=(1400^4-300^4)/(800^4-300^4)

200/x=(38416-81)×10^8/(4096-81)×10^8

1/x=4015×200/38335

X=20.95 joule/sec