a. If the surface in Problem 5.10 faces \(\mathrm{S} 45^{\circ} \mathrm{E}\), what are the incidence angles?

b. If the collector in Problem 5.10 has a cylindrical surface, what are the incidence angles on June 21 and December 21?

Problem 5.10

Calculate the incidence angle at noon and 9 a.m. on a fixed flat-plate collector located at \(40^{\circ} \mathrm{N}\) latitude and tilted \(70^{\circ}\) up from the horizontal. Find \(i\) for June 21 and December 21.