44. Light of wavelength 400 nm falls on a metal surface having a work function 1.70 eV. W inetic energy of the photoelectrons emitted from the metal? (c = 3.00×108 m/s， h=6.626✖10-34m2kg/s,leV=1.60✖10-19J)
(A) 4.5 eV
(B) 3.1 ev
(C) 1.4 eV
(D) 2.2 eV
(E) 1.0 eV
答案：C
統計：A:0,B:1,C:0,D:0,E:0
難度：計算中