1) Well, actually that never happens. You can plot the i-v curve of a resistor on the same plot as the photovoltaic cell. It will be a straight line through the origin, with positive slope -- in accordance with Ohm's Law.
Where the two curves intersect will be the operating point for that particular load resistance. This happens in the "+v,+i" quadrant, so it will have voltage less than the open-circuit voltage and current less than the short-circuit current.
2) That's a general property of all power supplies. Open circuit means just that, i.e. the load resistance becomes (for all practical purposes) infinite. i=v/R=v/∞=0
Incidently, the i-v curve of a photovoltaic cell is related to that of a diode. Take a diode's i-v curve and flip it about the v-axis (equivalent to defining the current's polarity in the opposite sense). Then shift the curve upward by an amount equal to the short-circuit current. Works for photodiodes as well as photovoltaic cells, as they are the same thing but with different applications.
This blog is about renewable energy sources. I am trying to cover the different types of renewable energy sources that can help in the generation of electricity.
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