A white roof reflects 80% of the solar radiation falling on it and a dark roof reflects 10%. Find the ratio of the power absorbed per unit area by the dark roof to that by the white roof (one decimal)

Question

A white roof reflects 80% of the solar radiation falling on it and a dark roof reflects 10%. Find the ratio of the power absorbed per unit area by the dark roof to that by the white roof (one decimal).

TestHub · Accepted Answer

The absorbed fraction is 0.90 for the dark roof and 0.20 for the white one. Ratio = 0.20 0.90 ​ = 4.5 . A white roof keeps the house cooler.

Physics - Heat & Thermo Question with Solution | TestHub

Doubts & Discussion