Perhaps you need the entire question. This is the entire question and not just part C.
1. Consider the diagram below, which depicts the geometry of a mountain.
North
20
20
South
a) Calculate the ratio of the intensity of incident solar radiation at noon on the north and south facing slopes if the solar zenith angle is 51°.
b) At what solar zenith angle will the north facing slope be completely devoid of solar radiation?
c) On March 21 at latitude 41°N, the average daily SW flux density is 275 Wm-2 at the top of the atmosphere [average amount of radiation received from sunrise to sunset].
M Fs = 275