1. (a) Consider a closed triangular box (with no charge enclosed) resting within a horizontal electric
field of magnitude E = 7.8x104 N/C. Calculate the electric flux through
(i) the vertical rectangular surface,
(ii) the slanted surface and
(iii) the entire surface of the box. Relate your answer to the flow of electric field lines.
To calculate the electric flux through different surfaces of the box, we need to use Gauss's Law. Gauss's Law states that the electric flux through any closed surface is equal to the net charge enclosed by the surface divided by the permittivity of free space (ε₀).
But since the box has no charge enclosed, the net charge enclosed is zero. Therefore, the electric flux through all the surfaces of the box will also be zero. This means that there are no electric field lines passing through any of the surfaces.
To relate this to the flow of electric field lines, we can consider that an electric field line represents the direction and strength of the electric field at a particular point in space. When there is no charge enclosed in a closed surface, the electric field lines passing through that surface are also zero. This implies that the electric field lines do not flow through the surfaces of the box. Instead, they either terminate on charges or continue from one charge to another outside the box.