The work function of a potassium is 2.0eV. When it is illuminated by light of wavelengths ${\text{3300 A}}^{\text{0}}$ photo electrons are emitted. The stopping potential of photo electrons is (in Volts)

[Plank’s constant $\text{h= 6.6}\times {\text{10}}^{\text{-34}}{\text{ms}}^{\text{-1}}\text{Js,}$$\text{1Ev =1.6}\times {\text{10}}^{\text{-19}}\text{J, C=3}\times {\text{10}}^{\text{8}}{\text{ms}}^{\text{-1}}$]