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Homework Statement
At Earth’s location, the intensity of sunlight is 1.5 kW/m^2. If no energy escapes
Earth, by how much would Earth’s mass increase in a day? (Radius of Earth is
6.37 × 10^6 m.)
The Attempt at a Solution
ok so, at anyone time, half of the Earth is lit.
so surface area lit = 1/2 x 4[tex]\Pi[/tex]r2 =
2.55x1014m2
intensity = 1500 W/m2
so energy per second on Earth = 1500 x 2.55x1014 = 3.82 x 1017 J
energy per day = 3.82 x 1017 x 60 x 60 x 24 = 3.3 x 1022
so E = mc2
so m = E / c2 = 3.67 x 105 kg
but the correct answer is half of this. so where did i go wrong? thanks for help!