question_answer

What is the work function (in eV) of the metal if the light of wavelength \[4000\overset{o}{\mathop{A}}\,\] generates photoelectrons of velocity \[6\times {{10}^{5}}m{{s}^{-1}}\] from it? (Mass of electron \[=9\times {{10}^{-31}}\text{ }kg;\] Velocity of light \[=3\times {{10}^{8}}m{{s}^{-1}};\] Planck's constant \[=6.626\times {{10}^{-34}}\text{ }Js;\] Charge of electron \[=\,1.6\,\times {{10}^{-19}}\,JeV{{\,}^{-1}}\])

Answer:

2.1