A body coated black at 600 K surrounded by armosphere at 300 K has cooling rate 80, the same body at 900 K, surrounded by the same atmosphere, will have cooling arte :

A body coated black at 600 K surrounded by armosphere at 300 K has coo

1.	A body coated black at 600 K surrounded by armosphere at 300 K has cooling rate 80, the same body at 900 K, surrounded by the same atmosphere, will have cooling arte :
Answer» `4r_(0)` `16r_(0)` `16r_(0)//3` `81r_(0)//16`. Solution :By Stefan.s law , `Eprop(T^(4)-T_(0)^(4))` `:.(E_(2))/(E_(1))=(T_(2)^(4))/(T_(1)^(4))""("NEGLECTING "T_(0)^(4)`) `:.(E_(2))/(E_(1))=((900)/(600))^(4)=(81)/(16)rArrE_(2)=(81)/(16)r_(0)`. Correct choice is (d).

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A body coated black at 600 K surrounded by armosphere at 300 K has cooling rate 80, the same body at 900 K, surrounded by the same atmosphere, will have cooling arte :

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