Question

Q.20) A black body of emissive
power 81 J/m's when it is at 300 k
and ordinary body of emissivity 0.8
when it is at 500 k What is emissive
power of ordinary body​

Answer 1

Answer:

200 Watts

Explanation:

Emissivity of body B, e=0.2 (Since e=a and a=(1−r−t)=0.2)

Emissive power of body B, E=(100)(0.2)=20W/m  

2

 

Power emitted =e.A=20×10=200Watts

I Hope It Will  Help