Question

Solar radiation is incident on a semi-transparent body at a rate of 900 W/m2 . If 150 W/m2 of this incident radiation is reflected back and 225 W/m2 is transmitted across the body, determine the absorptivity of the body. 

Answer 1

Given that;

Total incident radiation = 900 W/m²

Reflected Radiation = 150 W/m²

Transmitted Radiation = 225 W/m²

To Find;

Absorptivity ($\alpha$) = ?

Total radiation = Reflected radiation + Transmitted radiation + Absorbed radiation

Absorbed radiation = $900-150-225$ = 525 W/m²

Absorptivity = $\dfrac{\text{Absorbed radiation}}{\textsf{Total radiation}}$

= $\dfrac{525}{900}$ = 0.583