# Two photons of energy $2.5 \;eV$ and $3.6\;eV$ fall on a metal surface of work function $1.5\;eV$. The ratio of the maximum velocities of the photo electrons emitted from the metal surface is :

$\begin {array} {1 1} (a)\;1:4 & \quad (b)\;2:1 \\ (c)\;1:2 & \quad (d)\;1:\sqrt 2 \end {array}$

(d) $1: \sqrt 2$