# Field is not zero

A point charge $$q$$ is located at the center of a thin ring of radius $$r$$ with uniformly distributed charge $$-q$$. Find the magnitude of the electric field strength vector at the point lying on the axis of the ring at distance $$x$$ from its center with $$x >> r$$.

If the answer is in the form of $$\frac {aq r^b}{c\pi} \epsilon(x^d)$$ for positive integers $$a,b,c,d$$ with $$a$$ and $$c$$ coprime, give your answer as $$a+b+c+d$$.

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