It is suggested that the solar power incident at a point on the Earth’s surface depends on

I.     daily variations in the Sun’s power output

II.     the location of the point

III.     the cloud cover at the point.

Which suggestion(s) is/are correct?

A.     III only

B.     I and II only

C.     II and III only

D.     I, II and III

D

The first option concerning the daily output of the Sun’s power caused some confusion. The question does not ask about whether such variations occur (they do!) but rather whether they would lead to a change in power incident upon the Earth. Clearly they would, leading to D as the correct response.