1. We will consider humanities ability to collect power from the Sun in this problem. The Sun has a luminosity of L = 3.846 x 102 W, and a diameter of 1.393 million km. (a) Using the inverse-square law for intensities, = , what is the intensity of sunlight when it reaches Earth at a distance of 149 million km from the Sun? Give your answer in . (b) Now consider that the average total annual U.S. energy consumption is 2.22 x 1021 J. So, what is the average power requirement for the United States, in watts? (c) If solar cells can convert sunlight into electrical power at 30.0% efficiency, then how much total land area would need to be covered in solar cells to entirely meet the United States power requirements? Give your answer in square km. (d) If, in the future, an array of solar cells with a total surface area of 50,000 km? was positioned in orbit around the Sun at a distance of 10 million km, and this array converts sunlight into electricity at 60.% efficiency, then how much energy a year would this array generate? Give your answer in Joules