If $K_1$ and $K_2$ are the maximum kinetic energies of photo electrons emitted when lights of wavelength $λ_1$ and $λ_2$ respectively incident on a metallic surface and $λ_1 = 3λ_2$. Then -

$K_1<\frac{K_2}{3}$

$K_1=\frac{hc}{λ_1}-\phi$

$K_2=\frac{hc}{λ_2}-\phi$

$\frac{K_2}{K_1}=\frac{(\frac{3hc}{λ_1}-\phi)}{(\frac{hc}{λ_1}-\phi)}=\frac{3(\frac{hc}{λ_1}-\frac{\phi}{3})}{(\frac{hc}{λ_1}-\phi)}$

$\frac{K_2}{K_1}=>3$