Question

(a) Define electric flux. Write its S.I. unit.  

(b) A small metal sphere carrying charge +Q is located at the centre of a spherical cavity inside a large uncharged metallic spherical shell as shown in the figure. Use Gauss's law to find the expressions for the electric field at points P₁ and P₂.

(c) Draw the pattern of electric field lines in this arrangement.

Answer 1

(a) Electric flux over an area in an electric field represents the total number of electric field lines crossing this area and is given by the product of surface area and the component of electric field intensity normal to the area.

The S.I. unit of flux is Nm² C^-1.

(b) Let point P, is at a distance R from the centre O. S₁ is the Gaussian surface, then according to the Gauss's theorem