# A beam of light travelling along $x$ - axis is described by the electric field $E_y = (600 V/m) \sin \omega (t - x/c)$ then maximum magnetic force on a charge $q = 2e$, moving along $y$ - axis with a speed of $3.0 \times 10^7m/s$ is $(e = 1.6 \times 10^{-19} C)$
$\begin {array} {1 1} (a)\;19.2 \times 10^{-17}N & \quad (b)\;1.92 \times 10^{-17}N \\ (c)\;0.192 N & \quad (d)\;\text{None of these} \end {array}$