Surface of certain metal is first illuminated with light of wavelength λ_1=350 nm and then, by light of wavelength λ_2=540 nm. It is found that the…

Surface of certain metal is first illuminated with light of wavelength $\displaystyle \lambda_1=350 \mathrm{~nm}$ and then, by light of wavelength $\displaystyle \lambda_2=540 \mathrm{~nm}$. It is found that the maximum speed of the photo electrons in the two cases differ by a factor of $\displaystyle 2$ . The work function of the metal (in eV ) is close to : $\displaystyle \left(\right.$ Energy of photon $\displaystyle \left.=\frac{1240}{\lambda(\text { in } \mathrm{nm})} \mathrm{eV}\right)$