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