Six charge are kept at the vertices of a regular hexagon as shown in figure . If magnitude of force applied by +Q on +q charge is F, then net force on the +Q is nF. Find value of `n`

The opposite charges sitting on opposite ends of any diagonal will contribute to increase the force in the direction of negative charge.
Hence forces acting on central charge reduces like-

Net force acting vertically downwards=
Net force acting horizontally=
Hence net force acting on the charge=

Dear Student,
Please find below the solution to your problem.

If magnitude of force applied by +Q on +q charge =1
net electric force on the +Q is nF
WhenF = ​(1/4πϵ0)*​(q1​q2/r^2)​​
= 3×3q
=nF
or, n=9

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