Absorbing and emitting powers of a body are 10 and 8 respectively. Then (Ideal Black Body) IBB emissivity will be. . . . .

Absorbing and emitting powers of a body are 10 and 8 respectively. The

1.	Absorbing and emitting powers of a body are 10 and 8 respectively. Then (Ideal Black Body) IBB emissivity will be. . . . .
Answer» `0.2` `0.4` `0.6` `0.8` SOLUTION :A constant TEMPERATURE, all surface have equal absorbing and EMITTING power and their ratio is equal to absorptivity of (PERFECT) ideal black body. i.e. `(e)/(a)=EPSILON` Here, `e=8,a=10` `:.epsilon=e/a` `=(8)/(10)` `=0.8`