The magnetic field associated with a light wave is given, at the origin, by $B = B_0[\sin(3.14 \times 10^7)ct + \sin(6.28 \times 10^7)ct]$. If this light falls on a silver plate having a work function of $4.7$ eV, what will be the maximum kinetic energy of the photoelectrons? ($c = 3 \times 10^8$ ms$^{-1}$, $h = 6.6 \times 10^{-34}$ Js)