A beam of electromagnetic radiation of intensity 6.4 × 10 ^ - 5 W /...

A beam of electromagnetic radiation of intensity $6.4 \times {10}^{- 5} \text{W} / {\text{cm}}^{2}$ is comprised of wavelength, $\lambda = 310nm$ . It falls normally on a metal (work function $\phi = 2eV$ ) of surface area of $1{cm}^{2}$ . If one in ${10}^{3}$ photons ejects an election, total number of electrons ejected in $1s$ is ${10}^{x}$ . $\left(hc = 1240eVnm, 1eV = 1.6 \times {10}^{- 19}J\right),$ then $x$ is ___________