A conic surface is placed in a uniform electric field E as shown such that field is perpendicular to the surface on the side AB. The base of the cone is of radius R and height of the cone is h.

The angle of cone is $\theta$ as shown. Find the magnitude of that flux which enters the cone curved surface from left side. Don't count the outgoing flux. ( $\mathrm{\theta }$ < 45°)

• A

  $\mathrm{ER}[\mathrm{hcos}\mathrm{\theta }+\mathrm{\pi }(\mathrm{R}/2)\sin \mathrm{\theta }]$

• B

  $\mathrm{ER}[\mathrm{hsin}\mathrm{\theta }+\mathrm{\pi }(\mathrm{R}/2)\cos \mathrm{\theta }]$

• C

  $\mathrm{ER}[\mathrm{hcos}\mathrm{\theta }+\mathrm{\pi Rsin}\mathrm{\theta }]$

• D

  None of these