## Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (3rd Edition)

$1 Nm^{2}C^{-1}$
As we know, Electric flux $\phi$ through any surface is, $\phi= E.A=EAcos\theta$ Here, $\theta=\frac{\pi}{2}-30^{\circ}=\frac{\pi}{2}-\frac{\pi}{6}=\frac{\pi}{3}$, $E=200 N/C$ and $A= 10^{-2}m^{2}$ . Hence, $\phi=200 \times10^{-2}\times\frac{\pi}{3}$ $=200 \times10^{-2}\times cos(\frac{\pi}{3})$ $=2\times\frac{1}{2}=1 Nm^{2}C^{-1}$