For a certain body, the coefficient of absorption (absorptive power, a

1.	For a certain body, the coefficient of absorption (absorptive power, absorptivity) is 0.4. The body is maintained at a constant temperature. The radiant power of a perfect blackbody maintained at the same temperature is 5 × 104 W/m2 . Find the radiant power of the body at that temperature.
Answer» Data: a = 0.4, R_b = 5 × 10⁴ W/m² As the emissivity, e = a, we have, e = 0.4 ∴ R = eR_b = (0.4) (5 × 10⁴ W/m²) = 2 × 10⁴ W/m² This is the required quantity.

For a certain body, the coefficient of absorption (absorptive power, absorptivity) is 0.4. The body is maintained at a constant temperature. The radiant power of a perfect blackbody maintained at the same temperature is 5 × 104 W/m2 . Find the radiant power of the body at that temperature.

Answer»

Data: a = 0.4, R_b = 5 × 10⁴ W/m²

As the emissivity, e = a,

we have, e = 0.4

∴ R = eR_b = (0.4) (5 × 10⁴ W/m²)

= 2 × 10⁴ W/m²

This is the required quantity.