This graph represents current vs voltage for 200nm light shining onto Cadmium (Cd) which has a work function of 4.07 eV. In the following questions you will be explaining why this curve has the shape that it does.
![1756_Current vs voltage.png](https://secure.tutorsglobe.com/CMSImages/1756_Current%20vs%20voltage.png)
a) Why is current level for V>0? (Why is there a current when voltage is greater than zero?) Why does current start decreasing steadily at V<0?
b) Why does current go to zero at some negative voltage and what determines that voltage?
c) Draw on the graph to show how the curve will change if:
i) the intensity is increased.
ii) the light frequency is increased while the number of photons is held constant.