A flat panel solar collector is to be tilted at an angle to the horizontal to

A flat panel solar collector is to be tilted at an angle θ to the horizontal to maximize the amount of sunlight it can collect over the whole year. Once tilted, it is oriented toward the south (in the Northern Hemisphere). One might think that θ should be chosen to equal the latitude λ of the installation so that the Sun would be directly above the panel at noon on the equinoxes. Instead, if total insolation were the only concern, θ would be chosen to be less than λ. Explain why. Describe (but do not attempt to compute) how you would compute the optimal angle for a given location to maximize annual collection. Explain why, despite these considerations, in many practical situations θ may be chosen to be equal to or greater than λ.