A certain metal when irradiated by light $\left(\text{r}=3.2\times {10}^{16}\text{H}\text{z}\right)$ emtextts photoelectrons with twice kinetic energy as did photoelectrons when the same metal is irradiated by light $\left(\text{r}=2.0\times {10}^{16}\text{H}\text{z}\right).$ Then ${\text{v}}_0$ of metal is