試題詳解

20. The figure is a plot of stopping voltage V_stop versus light frequency f in a photoelectric experiment with a certain metal. What happens to the plotted line if we switch to a metal with a smaller work function?

(A) plot's slope increases, but horizontal intercept remains the same,
(B) plot's slope decreases, but horizontal intercept remains the same,
(C) plot shifts rightward and slope increases,
(D) plot shifts leftward, with no change in slope,
(E) there is no change in the plot.