When the light of frequency $2 V_{0}$ (where $V_{0}$ is threshold frequency), is incident on a metal plate, the maximum velocity of electrons emitted is $V_{1}$. When the frequency of the incident radiation is increased to $5 V_{0}$, the maximum velocity of electrons emitted from the same plate is $V_{2}$ . The ratio of $V_{1}$ and $V_{2}$ is