The electric field in a plane electromagnetic wave is given by $$ \overrightarrow{\mathrm{E}}-=200 \cos \left[\left(\frac{0.5 \times 10^3}{\mathrm{~m}}\right) \mathrm{x}-\left(1.5 \times 10^{11} \frac{\mathrm{rad}}{\mathrm{~s}} \times \mathrm{t}\right)\right] \frac{\mathrm{V}}{\mathrm{~m}} \hat{\mathrm{j}} $$ If this wave falls normally on a perfectly reflecting surface having an area of $100 \mathrm{~cm}^2$. If the radiation pressure exerted by the E.M. wave on the surface during a 10 minute exposure is $\frac{x}{10^9} \frac{\mathrm{~N}}{\mathrm{~m}^2}$. Find the value of $x$.