[" 6.In a photoelectric effect experiment,the graph between the stopping potential "V],[" and the frequency "v" of incident radiations on two different surfaces "X" and "Y" is "],[" as shown below : "],[],[" Answer'the following questions using Einstein's photoelectric equation : "],[qquad [" (a) What does the slope of the lines depict? Why is this slope same for both "],[" (b) "],[" () "],[" the lines? "],[" (c) Which of the two surfaces,"X" and "Y" ,has greater work function and why? "]]