Question

why do houses in Egypt have light coloured roof

Answer 1

The houses in Egypt have light coloured roof as we know that the Egypt is a desert area it will have more heat and dark colours absorb more heat .so to prevent heat the roofs are painted light

Answer 2

The answer simply related to phenomenon of radiation. The light colored surfaces are good reflectors of light(or heat waves or radiations ) and poor emitters, while black surfaces are good absorbers and good emitters of radiations. Thus, hot places like Egypt have light colored roofs to reflects most heat waves (only little part is absorbed).