The threshold frequency of a metal is f_0. When the light of frequency 2 f_0 is incident on the metal plate, the maximum velocity of photoelectrons…

The threshold frequency of a metal is $\displaystyle \mathrm{f}_0$. When the light of frequency $\displaystyle 2 \mathrm{f}_0$ is incident on the metal plate, the maximum velocity of photoelectrons is $\displaystyle v_1$. When the frequency of incident radiation is increased to $\displaystyle 5 \mathrm{f}_0$, the maximum velocity of photoelectrons emitted is $\displaystyle v_2$. The ratio of $\displaystyle v_1$ to $\displaystyle v_2$ is :