Why will a white roof keep your houses cooler in summer than will a black roof?

Why will a white roof keep your houses cooler in summer than will a black roof?

PROF WAQAR HUSSAIN

        White colour is great reflector of radiations and does not absorb any radiation at all. Thus, White colour repels heat rays. Therefore white roof absorbs comparatively less heat and reflects the heat outward. On the contrary, the black roof absorbs the heat and does not reflect it. Hence, the house with white roof is cooler.