Six charges are placed at the vertices of a rectangular hexagon as shown in the figure. The electric field on the line passing through point O and perpendicular to the plane of the figure as a function of distance x from point O is (xgtgta)

Explanation

This is basically a problem of finding the electric field due to three dipoles. The dipole moment of each dipole is `P=Q(2a)`
Electric field due to each diple will be `E=(KP)/(x^(3))`
The direction of electric field dur to each dipole is as shown inbelow
`E_("net")=E+2 cos 60^(@)=2E`
`=2((1)/(4pi epsilon_(0)))((2Qa)/(x^(3)))=(Qa)/(pi epsilon_(0)x^(3))`