The Sun radiates into a sphere with a radius equal to the Sun-Earth distance i.e., 149.6X106 km = 149.6X109 m.

 Area of surface = 4pr2 = 4p(149.6X109)2 = 2.81X1023 m2

 Area of Earth cross-section from question 1 = 1.273X1014 m2

 Power ratio = Area ratio = 2.81X1023/1.273X1014 = 2.2X109

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