Figure shows the stopping potential (V)versus frequency (v) graph for photoelectric effect in a metal. From the graph, The Planck's constant (h) is y×10−34Js. The value of y is

eV0=hν−ν0=hν−hν0              V0=heν−hev0   ………..(1)From Eq. (1) it follows that the slope of the graph is he. Therefore               h=e× slope =1.6×10−19×16.5−0(8−4)×1015=1.6×10−19×16.54×1015=6.60×10−34Js