Fluctuation in the Solar Constant The solar constant S is the amount of energy per unit area that reaches Earths atmosphere from the sun. It is equal to 1367 watts per m2 but varies slightly throughout the seasons. This fluctuation S in S can be calculated using the formula S = 0.034S sin c 2p182.5 - N2 365.25 d . In this formula, N is the day number covering a four-year period, where N = 1 corresponds to January 1 of a leap year and N = 1461 corresponds to December 31 of the fourth year. (Source: Winter, C., R. Sizmann, and L. L.Vant-Hull, Editors, Solar Power Plants, Springer-Verlag.) (a) Calculate S for N = 80, which is the spring equinox in the first year. (b) Calculate S for N = 1268, which is the summer solstice in the fourth year. (c) What is the maximum value of S? (d) Find a value for N where S is equal to 0.

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