The figure shows electric lines of force in a region. If $E_{\mathrm{A}}$ and $E_{\mathrm{B}}$ are electric fields at points $A$ and $B$ separated by distance $r$, then

 

A charge $q$ is placed at $O$ in the cavity in a spherical uncharged conductor. Point $S$ is outside the conductor. If the charge is displaced from $O$ towards $S,$ still remaining within the cavity,

Assertion: No two electric lines of force can intersect each other.

Reason: Tangent at any point of electric line of force gives the direction of electric field.

Two infinitely large charged planes, having uniform surface charge density $+\sigma$ and $-\sigma$ respectively, are placed along the $x-y$ plane and the $y-z$ plane respectively as shown in the figure. Then the nature of electric lines of forces in $x-z$ plane is given by