The magnetic field associated with a light wave is given, at the origin, by B=B_0[ sin (3.14 × 10^7) c t+ sin (6.28 × 10^7) c t]. If this light falls…

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