question_answer

A horizontal cesium plate (work function = 1.9 eV) is moved vertically downward at a constant speed V in a room full of radiation of wavelength 250 nm and above. The minimum value of v so that the vertically upward component of velocity is no positive for each photoelectron.

A) \[1.04\times {{10}^{6}}m{{s}^{-1}}\]

B) \[2.03\times {{10}^{7}}m{{s}^{-1}}\]

C) \[4.03\times {{10}^{8}}m{{s}^{-1}}\]

D) \[5.11\times {{10}^{9}}m{{s}^{-1}}\]