hv = hv0+ev0v0 = ehv−ehv0 On comparing this equation with the straight line equation, i.e y = mx + c The slope of v0 vs v is (v0 is stopping potential) (slope)1 = eh Likewise, hv = hv0 + Kmax or Kmax = hv - hv0 Thus, slope of Kmax vs v is (slope)2 = h ∴ (slope)2(slope)1 = ehh = e