where H is in Watts, A the surface area (m²), ? the emissivity that characterizes the emitting properties of the surface (dimension-less), a a universal constant called the Stefan-boltzman constant (- 5.67 * 10 ^ - 3 * W * m ^ - 2 * K ^ - 4) and T absolute temperature (K). Determine the error in calculating H for a R = 0.13 plus/minus 0.02 * r , e = 0.85 plus/minus 0.03 and T = 630 plus/minus 1 K, when there are the aforementioned uncertainties in the values of the parameters required to calculate H.