The work function of caesium metal is $2.14$ ev when light of frequency $6 \times 10^4 \;Hz$ is incident on the metal surface , photo emission of electron occur. what is the a) maximum speed of the emitted photo electrons

Question

$\begin{array}{1 1} 349 m/s \\ 349\;km/s \\ 349\;m/min \\ 349\;km/min \end{array}$