When the light of frequency 2${\upsilon _0}$ (where ${\upsilon _0}$ is threshold frequency), is incident on a metal plate, the maximum velocity of electrons emitted is v₁ . When the frequency of the incident radiation is increased to 5${\upsilon _0}$ , the maximum velocity of electrons emitted from the same plate is v₂ . The ratio of v₁ to v₂ is