A chargo q is uniformly distributed on a ring-shaped conductor of radius a. Find the field potential in an arbitrary point on the conductor's axis a distance I away from the plane in which the conductor lies. Using the relation between the potential and the field intensity, find the field intensity at this point.

Explanation

To find the potential, divide the ring into small segments and add up the potentials of these segments. The field strength is
`E=-(d varphi)/(dx)=-(q)/(4pi epsi_(0))(d)/(dx) (x^(2)+a^(2))^(-1//2)`
`=(1)/(2).(q)/(4pi epsi_(0))(z^(2)+a^(2))^(-1//2)*2x=(qz)/(4pi epsi_(0) sqrt((x^(2)+a^(2))^(3)))`