Dual Nature Of Radiation

A monochromatic beam of photons of intensity to $1.5 \mathrm{Wm}^{-2}$ and energy 11.2 eV is incident on a material of work function 4.8 eV . What is the maximum speed of photoelectrons emitted due to photoelectric effect if, only $0.53 \%$ of the incident photons eject photoelectrons. Given mass of electron $m=9 \times 10^{-31} \mathrm{~kg}$.