Dual Nature of Radiation

The magnetic field associated with a light wave is given, at the origin, by B = B₀ [sin(3.14 $\times$ 10⁷)ct + sin(6.28 $\times$ 10⁷)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 photo electrons ? (Take c = 3 $\times$ 10⁸ ms^$-$1, h = 6.6 $\times$ 10^$-$34J-s)