Sketch the graphs showing variation of stopping potential with frequency of incident radiations for two photosensitive materials A and B having threshold frequencies _A > _B.
(i) In which case is the stopping potential more and why?
(ii) Does the slope of the graph depend on the nature of the material used? Explain.

Graph showing the variation of stopping potential with frequency of incident radiations:



From the above graph, we can observe that,

i) The stopping potential is inversely proportional to the threshold frequency. Hence, the stopping potential is higher for metal B.

ii)The slope of the graph does not depend on the nature of the material used:

We know that,


Dividing the equation throughout by e, we get


On comparing the above equation with the straight line equation, we get

Slope of the graph = 
That is, the slope of the graph does not depend on the nature of the material used.