Work function of a metal is $2.35\,\text{eV}$. The maximum kinetic energy of photoelectrons emitted when it is illuminated by electromagnetic radiation whose electric component varies with time as $E = a[1 + \cos(2\pi f_1 t)]\cos(2\pi f_2 t)$ (where $a$ is a constant) is ($f_1 = 3.6 \times 10^{15}\,\text{Hz}$, $f_2 = 1.2 \times 10^{15}\,\text{Hz}$ and Planck's constant $h = 6.6 \times 10^{-34}\,\text{Js}$)