Question

The temperature of a perfect black body is
727°C and its area is 0.1 m². If stefan's constant
is 5.67 x 10 watt/m2-K4, then heat radiated
by it in 1 minute is :
(1) 8100 cal
(2) 81000 cal
(3) 810 cal
(4) 81 cal​

Answer 1

Answer:

I think the fourth answer is right

Answer 2

Answer:2

Explanation:

dq/dt= stefans const×A×(T)4

=5.67×(10)×. 1×(727+273)4=5670W

Now in 1 min

5670×60=340200J

So, in calories

340200×0.239=81000cal(1J=0.239cal)